- test-drb@ccmp.vtda.org - classiccmp.org

Possibly going up to VCF, stuff I would like to sell/get to proper people pdp8/12/HP stuff

by cz＠alembic.crystel.com

Hi all! I'm thinking about going up to VCF in Wall next weekend. I haven't been to it since it was the Trenton Computer Fest (think late 1990's) so I'm not sure what the protocol is on tailgating, trading stuff or whatnot. Appears that they have a "sale room" you drop things off in with prices. Ok.... Things I could "sell" if anyone's interested: HP1000e computer, dead power supply, basic boards, no advanced memory. HP9825B likewise does not power up, but it's there. Microvax 2 boards, stuff like that. Spare 11/24 CPU boards (I have a bunch, all work, no idea why I have all them) Stuff I could bring to get out of my house and into the right hands: Big box of pdp12 schematics. This came from my olden days when I had to turn up a pdp12 because it will not fit in a station wagon. Still it looks like board locations and a lot of 12 stuff. Big box, heavy to ship, easier to drive over. Ton of pdp8/12 IO cables. These are the black circular wire ones, I think negibus. There's also some posibus ribbon cables but I'll save those for my 8/L's. If you need a set, let me know. Stuff I'd trade for: AF01 A/D converter. I don't have Negibus anymore, but I did check/reform the power supply and hooked it up and things do light up. Bunch of extra channel cards (I think it might have all 64). Would trade for a memory box for an 8/L. Back to unearthing BLT.AI.MIT.EDU....... C

3 years

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Quantum ATL-7100 DLT Changer in SLC

by Tim＠Rikers.org

I have a Quantum ATL-7100 100 tape DLT changer. Last I checked it worked fine. It's almost as big as a fridge. I have around 100 tapes for it, not all the same density. It uses fast/wide scsi-3 differential for the drives. I think I have 2 working drives in the cabinet plus one or 2 separate external drives. I think my drives are DLT-7000 or similar which gives a total capacity of 7TB. Upgraded with SDLT 220 drives and tapes the chassis would have a capacity of 22TB. Anyone interested in picking this up in South Jordan Utah? (outside Salt Lake City). The only issues I know about it, is the tape loading pivoting door is not quite rotating correctly, and I replaced one of the AT power supplies with a unit that is NOT autoswitching. So if you want to run the unit on 220V instead of 110, you will need to change the chassis and the replaced internal power supply. It's really fun to load it up with tapes, then tell it to auto-shuffle them. I have the door hot wired so you can open the door while it's operating. Easy to restore the switch if you don't want to. Photos here: https://rikers.org/gallery/hardware-atl7100 Interested, please email directly, I don't check the list very often. Tim

3 years

5
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RCA COSMAC MS2000 MicroDisk Development System

by Rice43＠btinternet.com

Hi all, I?ve recently come across something i?ve soon realised really quite unusual. An RCA MS2000 MicroDisk Development System. I?m very green to the COSMAC scene, with this being my first 1802 machine. I?m very interested in knowing the pitfalls i may come across in restoring such a machine. I?ve had a quick cursory look over the machine, and it seems to be complete, with 2 RAM/ROM cards, CPU card, FDC and a (3rd party?) ROM programmer board, along with the PSU and floppy disk drives. It?s my understanding that these are pretty similar to the RCA Microboard development systems, which i believe are also pretty similar to the ELF ?homebrew? microcomputer this group revolves around. I?ve found some manuals on bitsavers,, a website on the Microboard system, along with disk images on the Emma02 emulator website, so I have a reasonable undertanding over what this actually is. I have a week off work next week, so am planning on taking my time on disassembling and checking the unit over next week. I?ll endevour to upload some pictures of said machine when i tear it apart. Thanks, Josh Rice

3 years

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Bob Lucky

by brain＠jbrain.com

I don't remember seeing this here, and not sure how many of you read his articles, but: https://spectrum.ieee.org/bob-lucky-obituary -- Jim Brain brain at jbrain.com www.jbrain.com

3 years

4
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Any CodeWright users: still have patch installers?

by dnm＠pobox.com

This is a long shot, but on the off chance anyone else on the list shares some of my particular weirdnesses, anyone got a line on the *patches* for Embarcadero (nee Borland (nee Starbase (nee Premia) CodeWright? I have the latest version Embarcadero sold (and maybe still sells?) as of not all that long ago -- 7.5 -- but it's basically patch level 3 (e.g., 7.5.3) instead of patch level 5 (e.g., 7.5.5). I'm hoping someone has the patch installers squirreled away somewhere, and that I can find that person. At least for Windows, patch installers were typically named something like "xcw753_4.exe", which would update an existing version 7.5.3 to version 7.5.4. Likewise xcw754_5.exe would update 7.5.4 to 7.5.5. Every now and again, I go looking for archives in The Wayback Machine, etc. or stashed away versions of the patch installers, but no dice so far. I've even attempted emailing folks who posted 10+ years ago or more on various fora about the patches/about CodeWright, but nothing has yet worked out there either. -- Daniel Moniz <dnm at pobox.com> [http://pobox.com/~dnm/]

3 years

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Lecture: A tour of Update's new premises, 2022-04-09, 19:00

by stueberahoo＠yahoo.de

Hi all, you're invited to the Update computer club[0] public lecture series "Updateringar"[1]! When: 2022-04-09, 19:00 CEST Where: https://bbb.cryptoparty.se/b/upd-0mo-m2u-aq8 A tour of Update's new premises In December and January 2021/2022 Update moved out of the Uppsala University IT department's basement into rooms of its own (thanks again to all our volumteers who put in a huge effort!). The new premises offer 150 m? of space for Update's collection and activities, with a dedicated area for exhibitions. What has happened since the move? With this online tour we invite you to take a peek into our new home and at what we've been working on in the last couple of months. We will give you an insight into current and future projects and show off some of our collection items. Bjarni Juliusson, Anke St?ber (Update) The lecture is free and open to everyone. Don't want to miss upcoming events? Subscribe to our low-traffic announcement list here[2]! Hope to see you there, Anke [0] https://www.dfupdate.se/en/ [1] https://wiki.dfupdate.se/projekt:updateringar [2] https://lists.dfupdate.se/postorius/lists/announce.lists.dfupdate.se

3 years

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UNIBUS powoer on/off spec

by jnc＠mercury.lcs.mit.edu

> the later "pdp11 bus hanbook" (which, as mentioned, does not seem to be > online yet, alas) Arck, I'm a moron; Paul has pointed out to me that this is, in fact, online at Bitsavers: http://www.bitsavers.org/pdf/dec/pdp11/handbooks/PDP11_BusHandbook1979.pdf It didn't show up in a couple of pages of results in a Web search for it, though. I have noticed that things on Bitsavers often don't show up high up in Web search results, unless you add 'bitsavers' to the search term. I have been told that at one point Google was 'downgrading' results that used plain HTTP, instead of HTTPS, because they were trying to push people to switch to HTTPS (this was when everyone was hyperventilating over the Snowden revelations). Given the near-ubiquitous use of HTTPS these days, I'd have thought that piece of 'information credit engineering' by our tech overlords was past its 'sell by' date, and now serves primarily to block people from finding the material they are looking for (as here). Noel

3 years

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Glass memory?

by anders.k.nelson＠gmail.com

Hey all, found this on eBay: https://www.ebay.com/itm/Corning-Glass-memory-/125087612899 I can't find any info on it - was it some kind of delay-line or magnetic laminate stack? Interesting!

3 years

12
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Short PDP-8 Memory Address Test..

by lbickley＠bickleywest.com

Continuing the debugging of my recently acquired PDP-8/E, I wrote an address test that's easy to enter from the front panel: --- # PDP8 Quick Address Test # Pass 1: Loads locations 23-7777 with their own address. # Pass 2: Tests each location for the correct address. If # it fails (address does not equal it's own address) then # the diagnostic halts with the error location in 22. # The contents of that location displays the error. # By Lyle Bickley # 0000 7600 CLA 0001 1021 TAD 21 0002 3022 DCA 22 0003 1022 TAD 22 0004 3422 DCA I 22 0005 2022 ISZ 22 0006 5003 JMP 3 0007 1021 TAD 21 0010 3022 DCA 22 0011 1022 TAD 22 0012 7041 CMA IAC 0013 1422 TAD I 22 0014 7440 SZA 0015 7402 HLT (ERROR!) 0016 2022 ISZ 22 0017 5011 JMP 11 0020 5000 JMP 0 (START OVER) 0021 0023 0022 0000 --- Cheers, Lyle -- 73 NM6Y Bickley Consulting West https://bickleywest.com "Black holes are where God is dividing by zero"

3 years

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UNIBUS powoer on/off spec

by jnc＠mercury.lcs.mit.edu

> From: Paul Koning > You might give a precise source citation on that page. Done: https://gunkies.org/w/index.php?title=UNIBUS_Initialization&curid=6842&diff… Don't complain to me if the publication data is skimpy; that's all that's in it! (I mean, we all know that DEC is in Maynard, but the book doesn't say it...) Noel

3 years

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Digital Control Applications with the TMS320 Family

by kevin.bowling＠kev009.com

Does anyone have a hardcopy of this book they'd be willing to part with? http://www.bitsavers.org/components/ti/TMS320xx/1991_TI_Digital_Control_App… USPS managed to lose the one I ordered but delivered me the damaged packaging with tire marks on it :( Regards, Kevin

3 years

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UNIBUS powoer on/off spec

by jnc＠mercury.lcs.mit.edu

So, I looked at the early editions of the "pdp11 peripherals hanbook", which have good, detailed discussions of UNIBUS operations (at the back; chapter 5, "UNIBUS Theory and Operation", in the 1976 edition), but in contrast to the level of detail given for master/slave operations, and bus requests and interrupts, the level of detail on power up/down is very low, especially compared to that in the later "pdp11 bus hanbook" (which, as mentioned, does not seem to be online yet, alas). So, I have transcribed that section, and posted it: https://gunkies.org/wiki/UNIBUS_Initialization I have yet to scan and post the associated timing diagrams (which are useful, but not critical); the desktop that runs my scanner is down at the moment, alas. (If anyone who has a copy would like to volunteer to scan them, that would be great.) Noel

3 years

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SETI@home (ca. 2000) servers heading to salvage.

by korpela＠berkeley.edu

>From here: https://setiathome.berkeley.edu/forum_thread.php?id=85870&postid=2096776#20… They are bog standard Sun Enterprise systems, drive removed and destroyed for privacy reason. They are only interesting for what they've done. By university rules, our group can essentially "permanent loan" them to a non-profit, but any sale or transfer of ownership is up to University Excess and Salvage. A bit of history disappearing, which is nothing new in this group.

3 years, 1 month

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Core memory

by bmr＠ringman.ch

On Fri, Apr 1, 2022 at 10:26 PM Marc Howard via cctech < cctech at classiccmp.org> wrote: > We need to onshore Nixie production now! ;-) > Gentle plug for https://www.daliborfarny.com/.

3 years, 1 month

3
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AlphaServer 2100s available

by a.carlini＠ntlworld.com

I have three AlphaServer 2100 systems in storage in the UK (Oxfordshire). The storage, however, is due to be demolished (soon, but no fixed date). I won't have room to store these three systems, so if anyone would be interested in offering them a home, then please get in touch! I can probably get some pictures in the next day or two. These systems were SMP Alphas and could sport as many as 4 CPUs. I'm not sure of the configuration of these systems but I can probably find that out soon. They have not been run since ~2003 so they may be in need of some TLC. OTOH they are not rusted to death so you have a chance of getting them back to life. Just so you know what you might be dealing with these systems are about: 700mm H x 430mm W x 810mm L. I can't find the weight in any of my references right now but they are very heavy. Three people can move them up a slight slope with some effort but you would not successfully lift it into a car (assuming that it would fit). I'm planning to dismantle them to move them (i.e. remove PSU/PSUs etc. until they are light enough to move). A tail-lift would probably be the sane way to go (and is, indeed, how they got to their current location. I'm hoping that someone can step forward and offer one or more of these machines a new home. Please contact me off-list (once you're sure you understand what you are getting into :-)). Antonio -- Antonio Carlini antonio at acarlini.com

3 years, 1 month

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The Vertical Plane

by trash80＠internode.on.net

This may be of interest to some list members, particularly those who have an interest in the BBC computer or just like Twilight Zone type stories. Apart from being extremely interested in classic computers I also like the old stories that surround these old machines. A while ago I stumbled across a story about a BBC computer (this is the short version) that had been lent out from a school l think (as they did in those days due to the cost of machines back then) and this BBC, despite apparently not being connected to anything, started displaying messages from the past (a previous land owner) and someone in the future. As I said this is the short version of the story - it's also referred to as the Dodleston Messages or even the Dodleston Files if anyone wants to Google it. One of the claims was that this BBC proved the existence of time travel - WOW, a big claim. So the story eventually found its way into a book, The Vertical Plane by Ken Webster (1989). I believe the book gets its title from the way scientists describe time. So being interested in the stories I started my world-wide hunt for a copy. That was tough. A new copy unobtainable, an electronic copy not to my liking - I like the real thing, used copies were monumentally expensive (apparently the first edition was highly collectable). So I resigned myself to maybe one day I would stumble across a copy in a used book shop or an Op Shop (aka Thrift Shop) or a second hand shop. I visit these regularly because its amazing what pops up in them. Much to my surprise in February this year a Second Edition of The Vertical Plane was published and of course obtained for me by my local bookshop. My take - a good yarn - yes, do I believe the story - no. Please note, I have no connection with the editor or the publisher. Kevin Parker

3 years, 1 month

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Looking For HP-UX 5.1 9000/200 Series Kernel Disk

by tangentdelta＠protonmail.com

Hello. I have an HP 9000/217 (9817) machine that I'd like to install HP-UX 5.1 onto. In order to do this, I need to find the boot disk containing the correct kernel, which has the part number "A98680B", and is described as "Multi-user kernel for S200". Alternatively, I could run just the single-user version of HP-UX 5.1, which has the part number of "A98670B". The disk images for HP-UX 5.1 on bitsavers.org and hpmuseum.net do not have this disk. I found these numbers in the HP-UX administrator manual. Page 370 lists the kernel disks and their contents. http://bitsavers.org/pdf/hp/9000_hpux/1985/97033-90049_HP-UX_System_Adminis… If anyone can point me in the right direction, it'd be greatly appreciated! Thanks.

3 years, 1 month

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PDP 11/24 - A Step Backwards

by jnc＠mercury.lcs.mit.edu

> From: "Rob Jarratt" > I did plug the connector back in, so that DCLO and > LTC are connected, I just removed the ACLO pin. Ah, OK, good. Pulling the pins from those Mate-n-Loc shells without the right tool is tricky; glad you did it, because as Brent Hilpert pointed out, having a working DCLO is important, to reset everything to a known state on power-on. > I didn't look for replacements last night. Is there a modern > equivalent? Not that I know of. Even if you found something with the same pin-out, supposedly DEC selected ones that were 'good enough'. I've never had an issue with NOS ones that I bought from vendors, though. > I may have found a source of NOS. Great; get several, they're a useful chip to have around; the QBUS uses them, as well as the UNIBUS. If the same place has DS8640's (the receiver), save on shipping (and ordering delays) and get a couple of those too. I say that because depending on what else you had plugged into the UNIBUS post ACLO failure, the -15V may have damaged them too. The M9312 (not sure if you had one of those, but the -11/24 manual says it's common in them) uses ACLO (via a DS8640). The KY24 seems not to (as far as I can tell from a quick look - negative results from a quick print scan aren't 100.00% reliable, whereas positive ones are), oddly enough. In EUB memory (not sure which you have), the MS11-L and MS11M MS11-P don't seem to, whereas the MS11-P _drives_ ACLO (through an 8881) - probably to prevent CPU startup until the ECC is cleared). Etc, etc. > I always marvel at how neatly those wires are done, I wish I knew how > to do such a neat job. The same way the old joke says one gets to Carnegie Hall, I expect! :-) (I wonder what the UK equivalent of the Carnegie is - the Royal Albert, probably?) Noel

3 years, 1 month

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PDP 11/24 - A Step Backwards

by jnc＠mercury.lcs.mit.edu

> The 'unused' gate in E52 is the one that the added wires from the ACLO > ECO went to; I wonder if it was damaged by the -15V, somehow? So, I checked, and the wire that goes from the plated-through hole next to the etch cut on E70p1 winds up at E52p4 (the bus line on that transceiver), thereby connecting the latter directly to UNIBUS ACLO (on pin BF1). So that's almost certainly what caused other gate(s) in E52 to fail. I think I have managed to trace where all the other two wires to that 'new' gate in E52 went to/from, to see exactly what the ECO is. Given that E52 is a transceiver, it was likely substituted for E70 so that the KDF11-U could also _drive_ BUS ACLO. I discovered that E52p5 (the new transceiver's input) is connected to E73p13 (an DS8640 quad NOR used as a bus reciver); that's in the upper left corner of K2. It's BUS PB L NOR BUS PA H - i.e. a parity error has been detected in memory - so it apparently then power-fails the system! The incoming BUF ACLO (E52p6) goes to a PTH next to E70p8. On the bottom, there's a trace from that PTH that goes to E66p13 - which is the inverter shown on K2 which converts BUF ACLO H to POWER OK H. So that probably the answer to my plaint about E70p1 being left floating: perhaps theres an etch cut somewhere that disconnected E66p13 from E70p2, so the former can now be driven by E52p6. I can't see one, but there's a trace from that latter PTH that dives under E70, and I can't see it well, but it looks like it goes to E70p2. It would be interesting to know what they did about the E70p2 -> E66p13 connection. Noel

3 years, 1 month

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PDP 11/24 - A Step Backwards

by jnc＠mercury.lcs.mit.edu

> does [disabling the MCLK counter via DCLO, asserted by the two > E126 monostable chain from ACLO] happen just on power-down, or on > power-up too? I'd need to understand how that two monostable chain > works in both cases, which I currently don't. (I only understand > monostables when pulses trigger them, not edges, which is a big part of > why I don't completely understand it.) So this was bugging me, so I hauled out my TI TTL databook and looked up the LS123. According to that, the 123 is triggered by the rising edge on the B (non-inverted) input, when the A (inverted) input is low (which it will be here; it's tied to ground). (Also by the falling edge on A when B is high, which we can ignore.) So I think that chain is probably triggered only on power-down, which will produce a rising edge on P FAIL. (Power-up will produce only a falling edge on P FAIL, once power is up and good.) (Note that the second monostable is triggered, also on B, by the -Q output of the first; i.e. by the 'falling' edge of the first's pulse. But see also at the bottom, below.) So that should happen (if I have correctly understood this, which is not certain, I'm just a software person :-) is that some time after P FAIL goes high - a delay set by the first 123 - the second 123 produces a pulse (of a width set by its RC pair) - which via E52 produces an assertion pulse on DCLO. WTF? (Not that we care in this machine's case, since i) it only happens on power-down, and ii) it's just a pulse, so it's affect on MCLK will be very transient; it can't cause it to stay off. My curiousity has been piqued, is all. :-) The TM does not, after a _thorough_ search (although there are a few mentions of power u/down, but not this), explin why, alas. (The TM for some _other_ -11 CPU, one which contains a similar circuit might, but I'm not _that_ curious! :-) My _guess_ is that the intent is to reset all devices to a good idle state, _before_ power actually goes out. (Don't ask me why it just doesn't use INIT, though!) The potential fly in the ointment of complete understanding is that a 123 can _also_ produce a pulse on a rising edge at the clear input - and there is some circuitry driving the clear input on the second 123. (The clear input on the _first_ 123 seems to be left hanging in space - odd!) It seems to be set off by the mysterious DGP03 signal, generated by the microcode - but the GP table on pg. 4-21 of the TM doesn't contain an entry for '3'? Unless it has a typo - there are two '5' entries. In which case it could be 'Toggle the HALT flip-flop (K6)' (which I don't see on K6, unless it's E78) but yah, pulsing DCLO will probably clear it, wherever it is! This machine is making my head hurt. Disconnect the bad ACLO, power it on, and see if the CLK LED comes on. if not, then we'll have to work out why not. Noel

3 years, 1 month

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Core memory

by paulkoning＠comcast.net

When I looked at that ebay listing of "glass memory" it pointed me to another item, https://www.ebay.com/itm/265623663142 -- described as "core rope memory". Obviously it isn't -- it's conventional core RAM. Interestingly enough, it seems to be three-wire memory (no inhibit line that I can see). It looks to be in decent shape. No manufacturer marks, and "GC-6" doesn't ring any bells. paul

3 years, 1 month

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PDP 11/24 - A Step Backwards

by jnc＠mercury.lcs.mit.edu

> It was quite a struggle to separate those nylon connectors, is there a > trick to it? You mean the Mate-n-lok's? Not really; just make sure the catch is released. What did you do about DCLO? (Oh, I think I see the answer, below.... looks like you're relying on the pullup on K3...) > When I powered on, the CPU LEDs did not light up. Two of them ('0' and '1') are just bits in a special register, and thus only do anything when the bootstrap code fondles them. When you get ODT running, you can amuse yourself turning them off and on manually! :-) > I did notice that the CLK LED flickered on briefly when I powered it > off. Interesting. Not sure exactly what we can deduce from that; but interesting. > I put a scope probe on TP1 (p152 of the PDF), there was no activity, > the pin remained high. Yes; the signal there (MCLK H) is more or less the same one that drives the 'CLK' LED (MCLK L); so no big surprise there. Still, that reduces the problem space to a small part of K1. > The problem now is that I expect I will need to probe various pins to > find out what is going on. But I don't have a Unibus extender and I am > reluctant to remove the backplane. From what I can tell in the > Technical Manual you can't install the CPU in other slots Basically right; the backplane and CPU are designed to have it go in slot 1. It _might_ work in other MUD slots, with some loss of functionality (e.g. slot 2 doesn't have grant lines; MUD slots won't have the 'UNIBUS Map board pesent' line - pin FE1, on K11, UB TO MA VIA UBMAP) but I wouldn't want to chance it, there might be a clash. > I am forced to tack solder probe wires to the chips, which works but is > time consuming. Any other ways? Sorry, I don't have any experience to suggest any; too well supplied with extender cards, so I've never had to resort to alternatives! > I *think* I have found something. There could be a fault in E52 (sheet > K6, p157 of the PDF). While K6 BUS DCLO L is +5V, I am measuring K6 BUF > DCLO H at an average 1.64V Yeah, that's wrong. E52 is bad, and will have to be replaced. (From the +5V on BUS DCLO, I guess you're relying on the pullup? DCLO on the UNIBUS, with the resistor network on the M9302, should be about 3.5V - but now I'm confused, even with the P/S connector unplugged, it should still be 3.5V or so. Oh well, it's late, the brain is powering down... :-) The 'unused' gate in E52 is the one that the added wires from the ACLO ECO went to; I wonder if it was damaged by the -15V, somehow? > logical 0 output should be 0.4V max Which is what you should be seeing. > I also measured K6 BUF DCLO L to be always low, suggesting it thinks > the K6 BUF DCLO H is a logical 1. Yup; and that definitely explains why the clock isn't running - BUF DCLO L is clearing E41 on K1. Anyway, you'll have to replace E52 (which will be a bit of a pain, with the 3 ECO eires tacked to it). The DS8641 is an old chip, no longer in production, so the usual suppliers may not have it, but there are some on eBait. Noel

3 years, 1 month

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PDP 11/24 - A Step Backwards

by jnc＠mercury.lcs.mit.edu

Finally found time to get to this one... > From: Rob Jarratt > However, there is a puzzle. On the CPU I found that the track from the > pull up resistor to E70 has been cut. I don't know about the "pull up resistor" part, but I have several KDF11-U's, and _all_ of them have the trace on the bottom of the card connected to pin 1 of E70 cut, in the exact same place (about 1/8" from the pin). This suggests that it's not a local mod (as you suggest below), but an 'official' DEC ECO. > This would suggest that E70 pin 2 is floating, which I think means that > K2 BUF ACLO H is also floating The input (pin 1) will be floating, but not the output (pin 2); TTL doesn't work that way, I think. I may have this wrong, but I think open TTL inputs float high, so BUF ACLO should be low. I looked, and I don't see any other traces (e.g. on the top side) going to pin 1. So I'm a bit puzzled that DEC allowed that input to float, as open inputs can lead to erratic operaton; they're usually tied high, or to ground. > K2 BUS ACLO L however has been patched to E52 pin 4, which is the > output of a gate on sheet K6. Can't say I understand why. Me neither; that's an unused (on the prints) driver in the DS8641 (center bottom of the page) - although that gate seems to have been fully wired up (wires to pins 4, 5 and 6) as part of the ECO. There is an ECO list on pg. 167 of the -11/24 prints (2 pages after K14), but I don't see an E52 in it anywhere. The puzzle here, if E70p1 is cut, and the output is low, is why the CPU clock isn't running. The -15V on BUS ACLO shouldn't have taken out any other semiconductors; it's not attached to anything else. (It will have run C6, on the lower right of the card, the wrong way, but i) I think that's a non-polarized item - and 100V rated, per the prints, and ii) I don't think that goes anywhere else, even if it's not.) So what's stopping the clock from running, then? Noel

3 years, 1 month

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PDP 11/24 - A Step Backwards

by jnc＠mercury.lcs.mit.edu

> From: Tony Duell > A short in FET Q15 on the bias/interface board in the PSU could do it. > The gate of that FET is driven from an LM339 comparator the -ve supply > of which is -15V. Ah; I hadn't even looked at the P/S prints. (Like I said, I'm really weak on analog: for digital, I have the advantages that i) although I'm basically/mostly a software person, the MIT CS department is part of the EE department, and they made sure that all the CS people had a decent grounding in the fundamentals of digital hardware; and ii) in my early years, I was involved in a number of actual hardware projects, including a UNIBUS DMA network interface that tuned into an actual product. So I'm pretty good with a digital circuit diagram, like these CPU prints. But analog stuff is still a mostly-closed book to me! :-) Anyway, I'm happy to let you provide the analysis of the P/S... :-) > From: Rob Jarratt > [Perhaps] something else on the CPU caused Q15 to fail (if indeed it > did). I'd guess 'unlikely' (if Q15 has failed); UNIBUS ACLO is connected, on the CPU card, to only a single gate (on K2), and that 383 ohm pull-up (on K3), and the 1K pF cap there (the purpose of which I still don't understand, unless it's just a smoother). Although I suppose that if that cap failed, shorted, maybe that could have taken out Q15 somehow. > Perhaps I should ... and disconnect ACLO, DCLO and LTC, they are all on > the same connector Now why didn't I think of just un-plugging that whole connector! Duhhhh! My only concern would be leaving inputs floating... DCLO, no problem; it has that pull-up on K3. (Ditto for ACLO, if the buffering input gate isn't dead.) LTC, let's see... It's on K6, upper left corner. I'm too lazy to work out what leaving that input floating will do, and, if it has bad consequences, trace out all the places it goes (it should be connected up to cause an interrupt, somewhere), but there's no point; the KW11 has an 'interrupt enable' that has to be set by software before it can do anything; so at the moment it's safe to just ignore it for now, and stay with a focus on getting the main CPU clock running. (LTC is not on the UNIBUS, so there's no pull-up on the M9302 for it the way there is for ACLO & DCLO.) So unplug that connector, and see if E70 (on K2, lower right corner) is OK. (Remember, the pull-up will give it an Ok input with BUS ACLO disconnected.) If yes, great, go check the main CPU clock. If not, time to i) see how far the rot has spread (e.g. have other gates in that package died - not sure what else is in there; not just looking at things connected to the output - on pin 2), and ii) decide how to repair or temporarily bypass. (Ditto for anything else that got taken out.) I'd be tempted to bypass it (since I doubt you stock 8837's - although I do :-) - ACLO handling isn't needed to get the CPU running. Tie BUF (not BUS!) ACLO to ground, I'd say, and we can move on to look at MCLK. > If that works then I think repair ACLO and see if anything on the CPU > is bad or anything else that might cause a short on the ACLO signal of > the bus. Well, your call, but i) working ACLO isn't needed to get the CPU running - and, in particular, to look for other problems that might be preventing it >from running, and ii) fixing ACLO isn't guaranteed to make the CPU work. I'd recommend 'keeping the eye on the ball', and focus on the main CPU clock, getting ODT running, etc. The ACLO issue(s) can be cleaned up at your leisure. Noel

3 years, 1 month

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PDP 11/24 - A Step Backwards

by jnc＠mercury.lcs.mit.edu

> and there is some circuitry driving the clear input on the second > 123. Never mind this section. I mis-read the print; the clear input is connected to an _input_ of the flop below (which is also tied high). Noel

3 years, 1 month

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PDP 11/24 - A Step Backwards

by jnc＠mercury.lcs.mit.edu

> From: Brent Hilpert >> ACLO is only used to trigger a 'power-failing' interrupt; CPU >> operation is otherwise un-affected by ACLO (so the CPU can get ready). >> DEC P/S's carefully sequence ACLO and DCLO such that on power-down, >> ACLO is asserted first (to allow the CPU to get ready); on power-up, >> DCLO is de-asserted first (the later de-assertion of ACLO is the >> signal for the CPU to start running). > a) "ACLO is only used to trigger a 'power-failing' interrupt" > b) "ACLO is the signal for the CPU to start running" > Only a, or a & b? Sorry, I tried to write only 10 words, when I should have just bitten the bullet and written 40. There are two different circumstances: i) AC power coming on, and ii) AC power going off. (Sorry if you already know this next, but I'm not skipping anything any more: DEC paid careful attention to both, as the PDP-11's were always intended to be able to deal well with un-attended operation over an un-expected power outage. So they had to shut down in an orderly way on ii), and start up in an orderly way on i). Having the operator press a 'reset' button after power-on was not an option! Of course, the software had to be written to handle it all, and not all of it did so; e.g. UNIX V6 didn't deal well with either, whereas RSTS-11 would go through an outage and automagically pick up exactly where it was when power went down.) So when I said "ACLO is only used to trigger a 'power-failing' interrupt", the un-stated circumstance was 'when AC power goes off'. The bit about "de-assertion of ACLO [on power-up] is the signal for the CPU to start running" is something I hadn't known, but just picked up (it's not anything I ever had to pay attention to before) from reading the "Initialization" section in the "pdp11 bus handbook" - which is not (alas) online. (Maybe I should scan, OCR and port that section; it's fairly short.) (There _is_ a "pdp-11 UNIBUS Design Description" document online: http://www.bitsavers.org/pdf/dec/unibus/UnibusSpec1979.pdf but alas it doesn't have anything like the detail given in the "pdp11 bus handbook". 2.5 there, "Initialization Section", has some text about ACLO, DCLO and INIT (which is generated by the CPU, not the P/S), but not much.) Here's what the "pdp11 bus handbook" says (pg. 54): "When [the processor] senses the negation of ACLO, [which happens after the negation of DCLO, which itself happens "5 useconds after DC power is within specifications" - i.e. plenty of time for all logic to reset itself to a known state, after good power is available to it all] the processor starts its power-up sequence." How that happens in the -11/24 I'm not sure; the -11/24 TM doesn't cover it, and the Fonz, which we don't have documentation on, will be involved. > Now these things may well not be a problem here; I'm just looking for > potential failure points because we're looking for an unknown fault by > isolating things, and it's best done without introducing new potential > problems, or at least being aware of the potential. Makes sense. > ACLO exercises influence over DCLO and hence the CPU clock via those > those monostables (we both) mentioned earlier. Right, I had forgotten about those - it was late, and my brain was shutting down as I was tired. > ACLO -edge: > ==> inverted (E70.2/K2) to +edge > ==> triggers FF (E67/K2_PFAIL) to latch high > ==> triggers MonoFF (E126/K6_AC_TIM) > ==> triggers MonoFF (E126.10-5/K6) > ==> asserting K6_BUF_DCLO_L for some period It's not clear to me what the _point_ of that all is; I had previously guessed that "there's a delay between the PFAIL H input .. and _the CPU_'s assertion of DCLO - i.e. if the P/S goes bonkers and indicates ACLO, and doesn't promptly (after a suitable short delay to allow for power-fail action) follow it with DCLO, as it is _supposed_ to, the CPU will indicate DCLO on its own - and do it on the bus so everbody else will freeze too." That might still be correct - I think that perhaps that path through the monostables only operates on power-down (but maybe I'n wrong there, I don't really understand completely how that all works) - on power-up, PFAIL H is going to be a falling edge - so will the two E126 monostables just ignore that? Alas, the -11/24 TM doesn't cover this, as far as I could find. AC TIM winds up being used on K1, on the monostable at top right, which I think generates a bus INIT pulse, when called for by the microcode (MIB14). No idea why they need AC TIM to clear that monostable. > ==> which disables MCLK counter (E41/K1) Right, but does that happen just on power-down, or on power-up too? I'd need to understand how that two monostable chain works in both cases, which I currently don't. (I only understand monostables when pulses trigger them, not edges, which is a big part of why I don't completely understand it.) > It may be that it just stops the clock temporarily: DCLO asserted resets > E67/K2_PFAIL, clearing it to register another ACLO / P FAIL. Could be; that's something else I don't understand completely; that flop's clear input depends on part on DGP06, which comes out of the E46 decoder on K1, which is again driven by the microcode. I'll have to look at the TM, and see if it explains that. > I thinks he's right to poke around the clock circuitry looking for > where the clock is being inhibited. Yup. I was hoping that if we just disconnected the busted ACLO, the clock would spring to life, and then we could move on to the next step(s), but maybe looking into that block in detail, e.g. to see if E41 is being reset by DCLO, would be the best way to go. Noel

3 years, 1 month

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PDP 11/24 - A Step Backwards

by jnc＠mercury.lcs.mit.edu

> From: Brent Hilpert > DCLO & ACLO behave as power-on-reset signals to the system. Minor nit: actually, I think it's DCLO which performs that function in a lot of places; see e.g. the latches on pg. K2 (pg. 153 of the PDF) and K7. (INIT, usually in buffered form, is used more widely for this function, but I doubly digress in that observation.) As I explained, ACLO is only used to trigger a 'power-failing' interrupt; CPU operation is otherwise un-affected by ACLO (so the CPU can get ready). DEC P/S's carefully sequence ACLO and DCLO such that on power-down, ACLO is asserted first (to allow the CPU to get ready); on power-up, DCLO is de-asserted first (the later de-assertion of ACLO is the signal for the CPU to start running). However, you make a good point with: > If they are allowed to just float up as the power supply comes up you > have no guarantees as to the end result ('end' meaning the state of > things after the power supply has come up) DEC specs state that DC power has to be up and stable 5 usec before DCLO can be de-asserted ("pdp bus handbook", pg 53). This is precisly so that everything is in a known state when operation commences. So I guess I'll go back to my original suggestion: disconnect the ACLO from the P/S (with its bogus -15V), leaving DCLO, so that it can properly set everything to a known state on power-on, and then you can see see if E70 has been fried, or is still working. > Manually connecting/disconnecting bus-ACLO to GND after power-up will > ... disable the clock. I can't see anything in the clock circuitry on pg. K1 (pg. 152 of the PDF), where all the clocks are generated, that looks at ACLO, or its inverted form POWER OK, or its latched form, PFAIL (both generated in the bottom RH corner of K2)? Did I miss something? All I can see is DCLO. I'm too burned out right now to check for uses of ACLO/POWER-OK/PFAIL, to see definitively what it does do; tomorrow. Noel

3 years, 1 month

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PDP 11/24 - A Step Backwards

by jnc＠mercury.lcs.mit.edu

> From: Brent Hilpert > So apparently I've been looking at the wrong +5V supply (H777) because > the rest of you are indeed looking at a different +5 supply (H7140), > both of which are in that same 11/24 pdf document That's because the H777 is the P/S for the BA11-L 5-1/4" box, and the H7140 is the P/S for the BA11-A 10-1/2" box - both of which are, quite reasonably, covered in the -11/24 print set. > I really wish when people are asking for assistance or talking about a > schematic or circuit they would include a link/reference to exactly > what they are looking at But everone probably _was_ looking at the same document - just different pages! Alas, DEC doesn't number _all_ the pages with a 'unique within the print set' identifier. Still, one could say 'page xx of the PDF'. Noel

3 years, 1 month

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Loss of Museum in Ukraine

by jnc＠mercury.lcs.mit.edu

> From: Murray McCullough > One can only hope that D. Cherepanov can rebuild his museum someday Is _he_ OK? (There are too many who aren't.) Noel

3 years, 1 month

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PDP 11/24 - A Step Backwards

by jnc＠mercury.lcs.mit.edu

> From: Rob Jarratt > I found these two signals and ACLO is low (-15V) 'Good news, bad news'... Bad is that something is seriously wrong there; 'allowed' values are 0v (asserted) and +3V (un-asserted). I'm worried that the -15V will have taken out some of the semiconductors that are 'listening' to ACLO (like E70, page K2 of the CPU prints, lower right corner) - and possibly some of the things that are connected to _them_. Good news is that i) this would definitely cause a problem, so we're closing in, and ii) even better, the machine doesn't actuallly _need_ the ACLO (or DCLO) signal from the P/S to function properly. Just disconect them (which may be a bit tricky; IIRC you've got a BA11-A - but you can pull the pin in the connector shell of the power harness from the backplane, details of that here: https://gunkies.org/wiki/DEC_power_distribution_connectors or, worst case, just cut the yellow wire to pin 4 of the 6-pin connector). At that point the pullups on ACLO (on the M9302 and the CPU - page K3 of the CPU prints - that's odd, there's a pullup to +5V there, but a cap to ground; the M9302 does indeed have the pull-up/down resistor pair on both ACLO and DCLO) should pull ACLO high and the clock should now run (CLK LED on) - unless the -15V killed something. If the machine then runs, it's up to you as to whether you get the P/S repaired so that ACLO work properly - your call. (I wonder how the -15V got to ACLO - I suspect a solder bridge from the prior repair - but knowing the answer is not important to getting the machine running.) > DCLO is high and the DC ON light is illuminated Good. > the CPU doesn't do anything presumably because ACLO is asserted. Yes. As long as the CLK LED is off, the machine will definitely be totally dead. If you can get it on, ODT should run (modulo issues yet to be sorted about the minimal functional machine - I'll post on that in a moment). Noel

3 years, 1 month

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PDP 11/24 - A Step Backwards

by robert.jarratt＠ntlworld.com

I had the H7140 PSU in my PDP 11/24 repaired a little while ago and I posted about it here: https://robs-old-computers.com/2022/02/10/pdp-11-24-progress/ I have since had the PSU fixed again and it came back a couple of weeks ago. When I installed it and applied power to the input, I heard a reassuring relay click. So I powered it on. The fans turned, but there was a crackle and I smelt something burning. I couldn't locate the smell, there were no lights on the CPU board, but the fans continued to turn. I had to leave it a few days and today I went back to it to check things a bit more carefully. All the power outputs of the PSU appear nominal. However, the ripple seems quite high, with an amplitude of 600mV on the +5V output: https://rjarratt.files.wordpress.com/2022/03/pin-1-5v-ripple.jpg. The DC ON light comes on, but the M7133 CPU LEDs show no activity whatsoever. There is no apparent damage to the CPU or to the M7134 that was also installed. So, I guess the component that blew up must be inside the PSU. Presumably, whatever the part is, it is stopping the CPU working, because previously the CPU did appear to show some activity, although of course it could still be a failure on the CPU. I am not sure what other outputs the CPU might depend on. There is the LTC signal for the line time clock, but I don't know if its absence would stop the CPU working. I have not been able to test the LTC signal as yet. Can anyone suggest what else the CPU might need? Or is it LTC? Regards Rob

3 years, 1 month

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PDP 11/24 - A Step Backwards

by robert.jarratt＠ntlworld.com

Its 600mV, but it is more of a spike than a ripple. Here is a trace: https://rjarratt.files.wordpress.com/2022/03/pin-1-5v-ripple.jpg Regards Rob > -----Original Message----- > From: Wayne S <wayne.sudol at hotmail.com> > Sent: 28 March 2022 23:15 > To: rob at jarratt.me.uk; Rob Jarratt <robert.jarratt at ntlworld.com>; General > Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> > Cc: Chris Zach <cz at alembic.crystel.com> > Subject: Re: PDP 11/24 - A Step Backwards > > How bad is the ripple? > Anyone on the list know what?s acceptable? > > > Sent from my iPhone > > > On Mar 28, 2022, at 14:46, Rob Jarratt via cctalk <cctalk at classiccmp.org> > wrote: > > > > > > > >> -----Original Message----- > >> From: cctalk <cctalk-bounces at classiccmp.org> On Behalf Of Chris Zach > >> via cctalk > >> Sent: 28 March 2022 20:57 > >> To: cctalk at classiccmp.org > >> Subject: Re: PDP 11/24 - A Step Backwards > >> > >>> I don't think the CPU is working at all. The reason being that there > >>> is absolutely no LED activity. Including an LED that is supposed to > >>> indicate a clock. Having hopefully eliminated all the power voltages > >>> it left me wondering if there was a fault on the CPU or in the PSU. > >>> Having had activity on those LEDs recently it seems most likely that > >>> it will be the PSU, particularly as *something* in there blew up. > >>> The only signal that I can identify that seems likely to have this > >>> kind of effect is LTC, but I don't know enough about LTC to know if > >>> its absence could cause the CPU board not to work at all, although I > >>> see above that you think it unlikely. I suppose the fault could be > >>> something I can't see on the CPU board, particularly as there do > >>> seem to be some quite large spikes, otherwise I am not sure if there > >>> is anything else from the PSU that could prevent the CPU getting going. > >> > >> I'm on a nice long train trip right now but I recently got my 11/24 > >> running again. One thing that baffled me was it would not do anything > >> on the serial port. No ODT, no nothing. > >> > >> Turns out you really need to make sure the slots are filled properly. > >> The CPU top, then the memory map, then for the next 4 boards one has > >> to be either a properly configured MS11-PL (the 128kw board) or the > >> memory boards specific to that type of 11/24. Or you have to put > >> G7273's in the CD slots. > >> > > > > I have been reluctant to put everything back in, in case the PSU fries > something. And the ripple I noticed is certainly something that bothers me. > Previously I had a burning smell from the memory board. I have since > replaced all the electrolytics on the memory board, but I have not tried > putting it back in the machine since. Just checking my notes, it seems I have > had *intermittent* lack of activity on the CPU LEDs before, so it may be > worth trying to put everything back in, although the ripple makes me > hesitant to do so. For the record, right now I have only the M7133, M7134 > and G7273 installed. > > > > > >> Next you need proper devices or G7273's in the next two slots and a > >> proper terminator in the left sockets of the last slots and a G7273 in the > center slots. > >> Only then will ODT work. > >> > >> Another oddity is that the 5.25 inch box has +5 and +12 I think and > >> the > >> 10.5 has +5 and +15. There are different memory boards that work in > >> one and not the other, or both depending on jumper settings that have > >> to be right. Unibus drives me bonkers sometimes with the number of > >> different voltages requires (+5, +12, +15, +20, -15, etc....) It > >> doesn't help that the +15 and +12 are on the same pins. > >> > >> Plus it's possible someone screwed with some switches, make sure they > >> are set properly (ie: default is a good start). > >> > >> If you're still stuck next week drop me a line and I'll fire up my > >> 11/24 and see if I can replicate your failure. > >> > >>> > >>>> > >>>> The first will tell you that i) the CPU is basically functional, > >>>> executing > >>> micro- > >>>> instructions, etc; ii) that the bus is basically functioning (for > >>> master-slave > >>>> cycles; DMA and interrupts will remain to be checked out); iii) > >>>> that the console port is working. (Yes, on the KDF11-U, the console > >>>> is on an > >>> internal > >>>> bus, and so in theory a machine could have the ODT 'front panel' > >>>> working, _and_ still have a problem with the bus, but depending on > >>>> the exact details of said problem, maybe not.) > >>>> > >>>> So, hook up a console, set the machine to 'halt', and power on. Is > >>>> console ODT working? If so, congrats, you win, go to stage ii) below. > >>> > >>> I had a console attached. There is nothing on the console. When I > >>> first got the machine I did get output on the console. But that was > >>> before the PSU first failed on me, which is quite a few years ago now. > >>> > >>>> > >>>> If not, you have a reduced area in which you have to investigate - > >>>> and > >>> you'll > >>>> need a 'scope of some kind to make any progress. (If you don't have > >>>> one, you're SOL. Get one.). In order i) is the CPU's internal clock > >>>> (and thus, probably the microcode) running? (At this point you will > >>>> need to consult > >>> the > >>>> "PDP-11/24 System Technical Manual", EK-11024-TM.) If so, is it > >>>> trying to > >>> talk > >>>> to the console's registers? (See Section 4.6 of the TM, "Internal > >>>> Address > >>>> Decode".) If so, is the UART working properly? (4.7 of the TM, > >>>> "Serial > >>> Line > >>>> Units".) > >>>> > >>>> If so, console ODT is running, you're now at stage ii): you can see > >>>> if the > >>> CPU > >>>> will run. Deposit a 0777 ('BR .') in a likely location (I usually > >>>> use > >>>> 0100 or 01000); read it back to make sure the write succeeded. (If > >>>> not, > >>> likely > >>>> either the UNIBUS or the main memory has a problem.) Start the > >>>> machine; the 'Run' light should come on - if you're lucky! > >>>> > >>>> Depending on which bin you wound up in, further assistance s > available. > >>> :-) > >>>> > >>>> Noel > >>> > >

3 years, 1 month

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PDP 11/24 - A Step Backwards

by jnc＠mercury.lcs.mit.edu

> From: Brent Hilpert > But the LED and CPU clock are not driven directly by that RC oscillator > - there's a bunch of logic in-between the oscillator and the LED / CPU > clock. Oh, sure; it was late (for me; the dog woke me up at AM today :-), and it had taken me a while to get even that far (find the freakin' thing), so I just wanted to pass the ball forward and crash! I saw the "STOP OSC H" signal feeding into the production of "PRE OSC L", but couldn't fully work out all the things that fed into that - and it now looks like that's not an important thing anyway, "MCLK H" is the one to look at. > [RC clock] => K1 OSC H/L > --> [4-bit counter w parallel load] => K1 MCLK H/L > --> LED It seems to me that the LED, being driven directly by MCLK L, should be flashing at the basic clock rate (i.e. dim to the eye) - so if it's totally off, MCLK L must not be running. So that's thing absolutely numero uno to investigate. > --> [driver] => K1 CHIP CLK H (fonz CPU clock) Yeah; the Fonz also gets "MCLK L" on pin 19, though - not sure what that's for. Eh, not important at the moment. > The 4-bit counter looks to be generating some additional phases Yeah, section 4.2 "Timimg" of the -11/24 TM talks about all the various clocks in some detail. > but it's also controlled by a bunch of other signals. One of those > signals is K6 BUF DCLO L which can hold the counter in reset, i.e. > disable the Master/CPU clock (and LED). K6 BUF DCLO L is derived > on-board from K2 P FAIL H Huh? BUF DCLO L is just BUS DCLO L, run through that DS8641 bus transceiver. But yes, because DCLO can stop the clock, checking ACLO and DCLO is priority numero uno in the debugging process, now. (Contrary to my previous fear, the CPU might be OK, and it might just be a power supply issue.) > which is derived from K2 BUS ACLO L I haven't bothered to check to see where BUF ACLO L (generated on K2) goes, but I assume it's used in power-fail trapping stuff. (ISTR that PDP-11 PS's sequence ACLO before DCLO, to allow power-fail trapping, before the machine is frozen as DC power actually goes low.) Likewise, not important at the moment. > which is input from BF1-in-funky-hex-box which I presume is a bus > connector pin. Yes; the ID ("BF2") is an indicator to that. > Even if ACLO is good, there's a whack of logic on the CPU board - > including two monostables - just to get from ACLO to DCLO The import of those two monostables isn't completely clear to me. However, notice that the output is fed through the DS8641 bus transceiver to _drive_ BUS DCLO; my _guess_ is that there's a delay between the PFAIL H input (which comes from BUS ACLO L) and _the CPU_'s assertion of DCLO - i.e. if the P/S goes bonkers and indicates ACLO, and doesn't promptly (after a suitable short delay to allow for power-fail action) follow it with DCLO, as it is _supposed_ to, the CPU will indicate DCLO on its own - and do it on the bus so everbody else will freeze too. Anyway, I think we've got as far as we can until ACLO and DCLO are checked. I'm upgrading the CHWiki KDF11-U page to cover the stuff that's not in the CPU chapter of the -11/24 TM, like the meaning of those on-board LED's, etc. Noel

3 years, 1 month

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PDP 11/24 - A Step Backwards

by jnc＠mercury.lcs.mit.edu

> From: Rob Jarratt > today I went back to it to check things a bit more carefully. All the > power outputs of the PSU appear nominal. > ... > Presumably, whatever the part is, it is stopping the CPU working, > because previously the CPU did appear to show some activity, although > of course it could still be a failure on the CPU. I am not sure what > other outputs the CPU might depend on. There is the LTC signal for the > line time clock, but I don't know if its absence would stop the CPU > working. I have not been able to test the LTC signal as yet. > Can anyone suggest what else the CPU might need? Or is it LTC? I'm going to start with some meta-comments, and then add some practical suggestions for how to proceed. Reading this, I'm guessing that you're a software person, right? Not that there's anything wrong with that (_I_'m basically a sofware engineer), but if one is going to collect and run (which inevitably means maintain/repair - it was ever thus, including BITD) vintage computers, you need to have mildly decent hardware skills. Yes, to some degree, one can lay this off on others (as has been done here with the power supply - something I'd do myself, as my analog skills are not very good), but I think developing some decent digital hardware understanding would really help. For instance, take your question about the LTC. To some degree, a complete, entirely accurate answer is dependent on the details of the software (bootstrap and/or OS). However, knowing how the LTC works, what the low-level details are of what the CPU hardware does with it, etc would tell you whether it is a cost-effective (in terms of overall 'getting the hardware working' project) thing to spend time on looking at, to begin with. (Parenthetical observation: I reckon that debugging _any_ issue, hardware _or_ software, is a process of 'what's the _cheapest_ [easiest, quickest, etc] test I can do that will produce the _maximal_ reduction in the area that the bug could be in. Rinse, repeat, until you've tracked the problem to its lair.) (You may discover, once you get the machine mostly working, that the LTC _specifically_ isn't working - at which point you can dive into it in detail. But until then, I'd ignore it. It's a relatively small aount of stuff, and the chance of a problem in there is small. And even if it's broken, the likely effects are small. There are better things to look at - below. Having a clear understanding of the machine's major functional units, and how they interact, would have made that clear.) So, in addition that that overview of the major functional units, you definitely need to know how the QBUS works (read the QBUS chapter in the "Microcomputer Products Handbook" or the "Microcomputer Processors" books). (Yes, I know, the -11/24 is a UNIBUS machine, but the two busses differ only in extremely minor details; if you fully understand one, you can learn the other in half an hour. And the -11/24's CPU is a KDF11 CPU, and uses the microcode ODT 'front panel' of the QBUS CPUs.) Having said that, and starting with the "All the power outputs of the PSU appear nominal" (which rules out a large area), this is the process I'd follow to reduce the area the problem is in as quickly as possible. (And maybe I should transform this into a 'fault analysis of QBUS (and some UNIBUS) PDP-11 systems' on the CHWiki.) You need to see if the CPU is _basically working. Two stages to that: i) is the ODT 'front panel' (in microcode) working, ii) is the CPU basically functional - i.e. can it fetch and execute instructions. Answers to those will greatly reduce the area in which the problem (if there's _only_ one - a possibility one must keep in mind). The first will tell you that i) the CPU is basically functional, executing micro-instructions, etc; ii) that the bus is basically functioning (for master-slave cycles; DMA and interrupts will remain to be checked out); iii) that the console port is working. (Yes, on the KDF11-U, the console is on an internal bus, and so in theory a machine could have the ODT 'front panel' working, _and_ still have a problem with the bus, but depending on the exact details of said problem, maybe not.) So, hook up a console, set the machine to 'halt', and power on. Is console ODT working? If so, congrats, you win, go to stage ii) below. If not, you have a reduced area in which you have to investigate - and you'll need a 'scope of some kind to make any progress. (If you don't have one, you're SOL. Get one.). In order i) is the CPU's internal clock (and thus, probably the microcode) running? (At this point you will need to consult the "PDP-11/24 System Technical Manual", EK-11024-TM.) If so, is it trying to talk to the console's registers? (See Section 4.6 of the TM, "Internal Address Decode".) If so, is the UART working properly? (4.7 of the TM, "Serial Line Units".) If so, console ODT is running, you're now at stage ii): you can see if the CPU will run. Deposit a 0777 ('BR .') in a likely location (I usually use 0100 or 01000); read it back to make sure the write succeeded. (If not, likely either the UNIBUS or the main memory has a problem.) Start the machine; the 'Run' light should come on - if you're lucky! Depending on which bin you wound up in, further assistance s available. :-) Noel

3 years, 1 month

4
6
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PDP 11/24 - A Step Backwards

by jnc＠mercury.lcs.mit.edu

> From: "Rob Jarratt" > Thanks for the lengthy reply. Glad to help - or try to. > As an aside I have also been trying to find a fault on a Pro 350 which > uses the same CPU chipset. I have a pinout but no datasheet. There doesn't seem to be as lot on the F-11 set. I looked in the DEC semiconductor handbook, and it's not there - although perhaps it had been dropped by the one I looked at (which was mostly uVAX stuff) as obsolete? If you look in the KDF11-A and KDF11-U Tech Manuals, there is a chapter on the F-11 chip set, as used in those cards, and that's better than nothing - it talks a fair amount about the low level details of how the various chips operate and interact, etc. > I don't think the CPU is working at all. The reason being that there is > absolutely no LED activity. Including an LED that is supposed to indicate > a clock. Looking at the KDF11-U prints, I finally found that LED (it's pretty low level - I was worried that it might be a bit in a register, and driven by software, but it's not, it's actually driven directly by the the CPU's internal clock signal; it's on page K1 of the prints, 'Clock, State Decode', in the very upper left corner). (The source of the CPU's internal clock is just an RC circuit, in the lower middle of that page, and the trim pot that's part of it - along the upper edge of the board - can be adjusted to set the clock speed 'properly', per the note at the back of the prints on the page which lists the configuration switches. The 2MHz crystal along the upper edge drives the baud rate generator.) > Having hopefully eliminated all the power voltages it left me wondering > if there was a fault on the CPU or in the PSU. If ODT isn't running, the problem is almost certainly in one of those two areas. > Having had activity on those LEDs recently it seems most likely that it > will be the PSU, particularly as *something* in there blew up. I'm not so sure. Those boards mostly just want +5V; looking a bit more, the CPU chips do seem to use +12V. The RS232 drivers will use +/-12V. I'm afraid that if i) it used to show activity, but no longer does so, and ii) the main voltages (+5V, +12V) look good, something on the CPU card has failed. But it will take a bit of digging to i) verify that, and ii) identify the fault. > The only signal that I can identify that seems likely to have this kind > of effect is LTC, but I don't know enough about LTC to know if its > absence could cause the CPU board not to work at all, although I see > above that you think it unlikely. I have yet to trace how the LTC signal is used in the KDF11-U, but on the KDF11-A, it not being there is a total NOP. (In fact, in the BA11-N/S type mounting boxes, there's a 'Clock Enable' switch on the front panel which turns the LTC signal off - and the machine runs fine with it off - except for the TOD clock not ticking.) That clock signal - totally different from the main CPU clock - is only used as an input to what is in effect a peripheral. > I had a console attached. There is nothing on the console. When I first > got the machine I did get output on the console. Not a good sign, alas. If you have a scope of some kind, and want to keep poking, I'd recommend that you start by seeing if the clock is running, and move forward from there. The KDF11-U prints are online, as is the KDF11-U Tech Manual. Skim the chapter on the CPU (4, I think), and then grovel around in the prints for a bit. Don't try to totally understand it all, just skim through it, so you know roughly where most things are. Noel

3 years, 1 month

2
1
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PDP 11/24 - A Step Backwards

by elson＠pico-systems.com

On 3/28/22 21:55, Jon Elson wrote: > On 3/28/22 17:22, Rob Jarratt via cctalk wrote: >> Its 600mV, but it is more of a spike than a ripple. >> > That's probably not real.? It looks like noise pickup from > the probe ground lead.? Try disconnecting the probe tip > and see if you still get similar signals.? I have seen > similar noise lots of times when measuring things with > switching power supplies.? The high frequency content is > pretty unlikely to be actually there on the power rails, > with a bunch of decoupling caps all over the boards. > > Jon >

3 years, 1 month

1
0
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Loss of Museum in Ukraine

by c.murray.mccullough＠gmail.com

Without getting political I was saddened to hear of the destruction of the Club 8-Bit museum in Mariupol, Ukraine. One can only hope that D. Cherepanov can rebuild his museum someday keeping classic computing in that part of the world alive. Murray--

3 years, 1 month

2
1
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FTGH: DEC Networks & Comm Buyer's Guide, Letterprinter 210/LA50 manuals

by toby＠telegraphics.com.au

Hi, Digital Networks & Communications Buyer's Guide 1987 April-June Also some DEC Letterprinter 210 and LA50 Printer manuals, ask for a list. For postage from Toronto Canada. --Toby

3 years, 1 month

2
2
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Webinar: Ethernet's Emergence from Xerox PARC: 1975-1980

by tom94022＠comcast.net

Ethernet invented in 1973-74 at Xerox PARC in Palo Alto, CA, evolved over many years. This April 13th Webinar will trace the history and development of Ethernet as a 10 Mb/s product up through the release of the DIX (DEC-Intel-Xerox) spec in 1980. This was the starting point for the ongoing IEEE 802.3 Standard activities. Speakers include Gorden Bell, Dave Liddle, Bob Metcalfe and seven other pioneers who were there for the transition. More detail at <https://r6.ieee.org/sv-techhistory/?p=1030> SVTHC website Register <https://www.eventbrite.com/e/ethernets-emergence-from-xerox-parc-1975-1980- tickets-301085664327> Tom

3 years, 1 month

5
4
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Installing an operating system on the 11/83 - update.

by rodsmallwood52＠btinternet.com

Hi All ????? I did find some RX50 images of the MicroRSX distribution. ???? So I fired up my DEC Celebris FX. It runs W95 and has a 3.5 inch floppy, a real RX33 5.25 inch drive and a CD-R. ?? Its accessible on my network so getting files onto it is not a problem. ??? So install putR.com , and transfer the image files. ? ? Huh! putR says the RX50 disk is write protected. Its not and the drive works normally with the disk from the MS DOS prompt. ? ?? So much for putR writes RX50's on RX33! ??? Rod

3 years, 1 month

15
38
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YouTube on the History of DEC

by r_a_feldman＠hotmail.com

A friend who used to work as a software trainer for DEC sent me the following link (https://m.youtube.com/watch?v=uIqlMfSCs0E), which points to an hour-and-a-half-long YouTube video from June 2021 about the history of DEC. It is a Zoom presentation from the Maynard Public Library done by a local newspaperman. It is fairly general, but was attended by a number of former employees, some of whom made comments.

3 years, 1 month

1
0
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FreHD

by bill.gunshannon＠hotmail.com

Here's one for the memory banks. I have a number of TRS-80's. Back when they first came out I bought a couple of the FreHD Hard Disk Emulators made by Fred Vecoven. They worked great and made life a lot easier. Then, I had reason to put everything away for a long rest. I just pulled them out and set them up again. Neither of them does anything. As a matter of fact, in my 4P they even keep the system from booting from floppies. Anybody else run into something like this? Is there something that would go dead if they sat idle for several years? I checked the CR2032 batteries and they are still alive so it's not like they ran out of power or anything. Any hints? bill

3 years, 1 month

2
1
0 0

MAN-3A display

by charlesmorris800＠centurytel.net

Looking for a couple of MAN-3A (single character, seven-segment red LED display) to restore a '70's pocket calculator. One digit is missing a segment. I had another 3A in my LED drawer - and IT has a different bad segment... aargh. No luck searching the usual places online. Can anyone help? thanks.

3 years, 1 month

1
0
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DEC ME11-L core memory expansion unit drawings

by jnc＠mercury.lcs.mit.edu

> From: Steven Malikoff > I have finally got around to scanning the print set for the DEC ME11-L > memory expansion unit Ah, thanks for that. The prints for the boards are available, in the PDP-11/05 Engineering Drawings (on pp. 115-137), but the MF11-L backplane was previously missing. (The -11/05 generally mounts MM11-L sets in the main CPU backplane, so the MF11-L backplane is not included in the -11/05 prints.) It is the non-parity MF11-L backplane (DEC part number 54-09959), not the parity one (part number 54-10331), though. (My theory is that the non-parity version can be upgraded to parity with an etch cut, and some added wires, FWIW.) Noel

3 years, 1 month

1
0
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DEC ME11-L core memory expansion unit drawings

by steven＠malikoff.com

I have finally got around to scanning the print set for the DEC ME11-L memory expansion unit and you can find it at https://archive.org/details/dec-me-11-l-core-memory-system-engineering-draw… The quality is acceptable given that the office supplies shop where I (DIY) scanned them on an A3 scanner only allowed output as JPEG or PDF (undoubtedly wrapped as JPEGs inside) so I thought there was no point degrading any more than necessary with editing the JPEGs to another format just to re-save them. I just bundled the raw scanned pages as-is and it looks fine. There's also some miscellaneous fragments for the M7050, M715 and M840 module drawings which came with the ME11 set. Steve.

3 years, 1 month

1
0
0 0

ID UV erasable PROMS used on an IBM PC board?

by organlists1＠sonic.net

I cannot find a datasheet by any of the numbers silkscreened on these ICs. Could these be proprietary IBM P/N numbers? https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0 No need for a Dropbox account, close the login pop up and you can view the image. Thanks Don Resor

3 years, 1 month

7
22
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Searching cctalk archives?

by ccth6600＠gmail.com

I came across a reference to a cctalk message from 9 September 2006 and would like to read the rest of the thread with the subject "PDP-8m Console Switch Problems - fixed!". Unfortunately it appears that the cctalk archive does not go back to 2006. Is there some place with the complete cctalk archive or at least back to Sept 2006? I have also been trying to search the cctalk archive, but short of downloading every month and unzip it, there appears to be no easy way of searching. What do experienced cctalk members do? Thanks Tom Hunter

3 years, 1 month

3
4
0 0

DEC DC319A DLART (DL11 Compatible Asynchronous Receiver-Transmitter)

by pbirkel＠gmail.com

In case anyone else has been looking some of these, there is a listing for multiple tubes-of-11 on eBay at a moderate price: https://www.ebay.com/itm/123710245814 QTY-11 PCS. AMI SEMICONDUCTOR DC319 C04090 Integrated Circuit - (UIC 40378901) It's documented in the DEC Semiconductor Data Book, Volume 1 (1987), pages 3-27 through 3-41: http://bitsavers.org/pdf/dec/semiconductor/ -----

3 years, 1 month

1
0
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Re: Unusual “gold” IC chips?

by bmr＠ringman.ch

Those look like "stripline" RF/microwave packages. PCBs will have cutouts for the package body, so that the leads can be soldered flat (no bends) directly onto impedance-controlled leads on the board. On Tue, Mar 22, 2022 at 6:17 PM Oldcompu via cctech <cctech at classiccmp.org> wrote: > Anybody know what these are? Maybe RF related? Found on a box of computer > ships. > > https://share.icloud.com/photos/0294pRVHPFQMShUZic2vFvneg > > >

3 years, 1 month

2
1
0 0

NEW CONTRIBUTION TO US CALL-A-COMPUTEER BIG 3 INCH 3 RING AS NEW TIMESHARE MANUAL

by couryhouse＠aol.com

NEW CONTRIBUTION TO US "CALL-A-COMPUTER"? PILLSBURY? TIMESHARE...? ?WHAT? SYSTEM WAS? THIS? RUN ON ?? ? ?IT IS A? BIG 3 INCH 3 RING AS NEW TIMESHARE MANUAL.? THANKS? ED#? ? SMECC MUSEUM

3 years, 1 month

1
0
0 0

ID UV erasable PROMS used on an IBM PC board?

by organlists1＠sonic.net

This is the CPU board out of a first generation 1982-83 IBM Electronic 85 Typewriter (Electronics Driven Selectric). I was looking to archive the software/firmware from these. The machine was exposed to some dampness. Corrosion has ensued on the interface connector between the CPU and driver boards. The next year, more energy efficient memory ICs were used. Memory power failure back up only consisted of 3 AA batteries and could last up to one year. The predecessor (this board) required 6 AA size Nicads and would only retain memory for a few hours. IBM using their apparently very large stock of OLD aluminum covered ICs in as many products possible I guess. Don Resor -----Original Message----- From: wrcooke at wrcooke.net <wrcooke at wrcooke.net> Sent: Sunday, March 20, 2022 7:13 PM To: D. Resor <organlists1 at sonic.net> Subject: Re: ID UV erasable PROMS used on an IBM PC board? > On 03/20/2022 8:59 PM D. Resor via cctalk <cctalk at classiccmp.org> wrote: > > > I cannot find a datasheet by any of the numbers silkscreened on these ICs. > > Could these be proprietary IBM P/N numbers? > > https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0 > > No need for a Dropbox account, close the login pop up and you can view > the image. > > Thanks > > Don Resor More details would help. What is the board? Do you know at what address in the PC memory map they fit? Based on the info you gave and the picture I would bet $1 they are standard 2764 chips. The 2764 was the first standard chip to have 28 pins. The size of the die visible through the quartz window is consistent with 2764 (as opposed to 27128 or 27256) and the fact there is room for 3 which would give 24K total. The PC didn't have a lot of places in the memory map that would allow more than 24K. Three 27128s would be 48K (a LOT in those days) and the 27256 would be 96K. I can't help with the part numbers. But I doubt they are IBM proprietary. The vast majority of chips used in the early PC line were standard from other companies. Will

3 years, 1 month

1
0
0 0

ID UV erasable PROMS used on an IBM PC board?

by organlists1＠sonic.net

I cannot find a datasheet by any of the numbers silkscreened on these ICs. Could these be proprietary IBM P/N numbers? https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0 No need for a Dropbox account, close the login pop up and you can view the image. Thanks Don Resor

3 years, 1 month

2
1
0 0

restoring a Silent 700 Model 765

by spectre＠floodgap.com

I found my old Model 745 in storage and other than needing a print head clean and adjusting the printer contrast, it works splendidly. It has the manual and I've got some plugs to build it an RS-232 connector when I find some more round tuits. This whetted my appetite for other 700s, including the (in)famous bubble memory 763/765. I was able to land a set of 765 ASRs. One of them came with Telenet transcripts from The Source (various logins from 1978 to 1980), which was really cool reading. I'll scan these. However, neither of them work. Both power on, but they immediately go into COMMAND mode and sit there, which appears to be abnormal behaviour based on what I'm reading in the service manual (thanks, Bitsavers!). The NUM LOCK switch works and the paper advance works, but nothing else appears to elicit a response. One of them advances the page and acts like it's printing the command prompt, but the other one doesn't even do that. The service manual suggests I need to replace both the TMS 9980 and 8080 boards, which would really suck. I'm hopeful that the one that's "more active" has a working 9980 board and I can use the 8080 board from the other one. (I haven't even gotten to the bubble memory yet.) Anyone repaired these units or have an idea of a repair strategy other than replace damn near everything? TELENET 303 8A TERMINAL= @C 301 24 301 24 CONNECTED DIALCOM NETWORK SYSTEM 10 -- ------------------------------------ personal: http://www.cameronkaiser.com/ -- Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com -- Simplicity is the ultimate sophistication. -- da Vinci ---------------------

3 years, 1 month

2
3
0 0

restoring a Silent 700 Model 765

by spectre＠floodgap.com

>> 301 24 CONNECTED >> DIALCOM NETWORK SYSTEM 10 >> > Please do scan these! It is hard as hell getting info on The Source > and also on Dialcom! Yes, I definitely plan to transcribe them. There is potentially some copyrighted material here but I think I can just excerpt that and still include all the rest of the login process, etc. Still, would be nice to get the terminal itself working and see what's in the ASR's bubble memory, assuming that's still operational, so any ideas people have would be appreciated. -- ------------------------------------ personal: http://www.cameronkaiser.com/ -- Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com -- mouse, n: A device for pointing at the xterm in which you want to type. ----

3 years, 1 month

1
0
0 0

General Data? Computer Equipment Auction - GSA

by mark.kahrs＠gmail.com

The LSSM is very interested in this machine for public display. It would complement the museum's collection of PDP-11s and other 16 bit machines.

3 years, 1 month

9
21
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LSSM is chasing this, was Re: General Data? Computer

by dave.g4ugm＠gmail.com

I missed a lot of this because g-mail decided to bounce some e-mails. I would like to make a couple of observations:- 1. Many real accredited museums have a smaller percentage of their artifacts on display than private collectors. In the UK both TNMOC and the Science Museum Group have large quantities of hardware that is not displayed. The science museum usually catalogues it but it is not really helpful if you can't see it. 2. All the private collectors I know are very happy to show and demonstrate what they have. It might not be catalogued so well but generally they want to show it off.... Dave G4UGM (Now feeling guilty because what I have is neither catalogued or on display)

3 years, 1 month

3
3
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IBM 5110 (5100) schematics ?

by bhilpert＠shaw.ca

Does anyone have or know whether the schematics for the IBM 5110 or 5100 are available? And the tightly related question of whether anyone has done ROM (ROS) dumps? There are some service manuals on bitsavers, they are field-service board-level manuals, mostly step-by-step problem resolution guides, no schematics. As a system, it's small enough to be reverse-engineered, in that regard it's tractable. However, it's implemented using IBM's mid-70s PCB and IC technology, increasing an RE effort by a couple orders of magnitude if not approaching impossible, unless one were to develop some robotic probing system and software. There was a 5110 on ebay, non-working, that a friend had some interest in. It was quite a gamble at the price, in the absence of real tech info. ... Apparently it's been delisted, so my question is just curiousity at this point.

3 years, 1 month

4
4
0 0

WTD - Oregon/Taumetric M68000 Pascal and Cross Assembler (VAX/VMS)

by classiccmp＠philpem.me.uk

Hi all, Does anyone happen to have a copy of these squirrelled away? - Oregon Pascal M68000 -- cross compiler for VAX (or any other host platform). Probably called "P68.EXE" or something similar. - Oregon / Taumetric M68000 Cross Assembler for VAX (or any other). Probably called "MASM.EXE" or similar. - Oregon / Taumetric M68000 Linker for VAX (or any other). Probably called "MIL.EXE" or similar. The assembler and linker might be ports of Motorola's M68KMASM and M68KLINK -- so something equivalent which takes the Motorola-format .SA files and spits out .RO files should work instead. I've been tasked with getting some ancient code building again, and as usually happens, the "backup" is incomplete... Thanks, -- Phil. philpem at philpem.me.uk https://www.philpem.me.uk/

3 years, 1 month

1
0
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IBM 5110 (5100)

by organlists1＠sonic.net

Was the computer auction in question a 5100 or a 5110? Presently I see there is a 5110-C for sale https://www.ebay.com/itm/294865912729 There were also a 5110 with 8" external drives and a printer which sold: https://www.ebay.com/itm/304377532685 Don Resor

3 years, 1 month

3
5
0 0

Does anyone/museum test disk packs?

by barythrin＠gmail.com

I was visiting a new thrift store and saw a disk pack they had. I joked that mine are just fun display/conversation pieces. Do the giant drives suffer the same head crash issues that a bad zip disk can do or are these safe if someone actually wanted to see what was on them?

3 years, 1 month

6
7
0 0

Does anyone/museum test disk packs?

by jfoust＠threedee.com

At 08:25 PM 3/16/2022, John Herron via cctalk wrote: >I was visiting a new thrift store and saw a disk pack they had. I joked >that mine are just fun display/conversation pieces. Wait.... you bought it, right? Was it $2? - John

3 years, 1 month

1
0
0 0

Commodore vic 20 poweroff

by bryce.diedrich＠intel.com

Just got a Commodore Vic-20. What is the safest way to power it off when I am done using it? Bryce Diedrich

3 years, 1 month

9
12
0 0

VCF East 2022

by mloewen＠cpumagic.scol.pa.us

Exhibitors wanted! Deadline to apply is April 1. Exhibits are NOT limited to the shows two main themes. "Ever wonder about the roots of today?s technological society? Did you spend Covid nostalgically playing old video games from the past on an emulator? Do you want to get hands-on with computers ranging from the 1960s thru the early 1990s? Come to the Vintage Computer Festival East in Wall, NJ on April 22nd thru April 24th, 2022. On Friday, April 22nd, there are classes in everything from programming the Apple II computer to "learn to solder" sessions for both kids and adults. You can even solder together your own Intel based computer with our partner GlitchWorks. On Saturday and Sunday (April 23rd & 24th), join us for hands-on exhibits of vintage and classic computers along with talks from the people who were at the beginning of vintage computer history. Learn how vintage computers lead to today's world of technology becoming commonplace instead of niche hobby. This year we have two themes for our weekend talks: Women in computing and Computers for the Masses. Talks include a reunion of Commodore employees talking about their days working at Commodore Computers as well as the creators of the Commodore Vic-20 and C64. Talks by Margaret Morabito, the editor of RUN magazine. Learn the history of video game programming starting with the Atari 2600 to modern times with Burger Becky a long-time veteran of the video game industry. Consignment sales will be open all weekend where our members will be selling everything from vintage Apple to Zenith computers and everything in between, as well as parts for computers, peripherals, and other vintage computer equipment. Who knows, you may find the items to complete your nostalgic journey back to the 1980s. Will you find the personal and home computer that you have been looking for? Learn more about the Vintage Computer Festival East at https://vcfed.org/wp/events/vintage-computer-festival-east"

3 years, 1 month

1
0
0 0

Vic-20 Power off.

by richardrpope2＠gmail.com

Diedrich, Just unplug it. I owned one for years. Thanks, Richard Pope

3 years, 1 month

1
0
0 0

Seeking a MC75325L Dual Memory Driver

by pbirkel＠gmail.com

I have here in my hands a DEC H222A (16Kx18), part of a MM11-DP, that took a blow at sometime in the past. In consequence there are a number of small parts damaged (snapped diode, crushed axial electrolytic, chipped mica capacitor, cracked/broken SIP resister net) but those all appear to be relatively easy to replace. What's not so easy to replace is the MC75325L Dual Memory Driver (L = Ceramic) that was de-lidded in the process :-<. I am wondering whether anyone has one of these ICs in their spare parts drawer that I could acquire? I do see a MC75325P (plastic) on eBay at littlediode_components for ~20USD, plus a surprisingly modest shipping charge (Royal Mail International). UTSOURCE claims to have a supplier of the ceramic part "new", with a significantly higher shipping charge. Before I go with the ceramic part (IMO not the sort of packaging that gets . remarked) I thought that I would check here for alternative sources. Thank you, paul

3 years, 1 month

3
2
0 0

Found! Ge 115 computer brochure

by couryhouse＠aol.com

Found! Ge 115 computer brochure where can I find the computer? Sent from the all new AOL app for Android

3 years, 1 month

5
11
0 0

Interface for a HP 712 workstation - A2263-66536

by jesse＠cypress-tech.com

This is a long shot but would anyone have an interface card for a HP 9000 712 HP-UX workstation. The part number is A2263-66536 and its a LAN card.. If anyone has one that they want to sell, let me know. Thanks Jesse Cypress Technology Inc jesse(at)Cypress-Tech.com

3 years, 1 month

1
0
0 0

gcobol

by paulkoning＠comcast.net

Saw a note on the GCC list that I thought some here might find interesting: it announces the existence (not quite done but getting there) of a COBOL language front end for GCC. Interesting. For those who deal in legacy COBOL applications that want a more modern platform, I wonder if this might be a good way to get there. Run old COBOL dusty decks on Linux, yeah... I wonder if I can make build that front end with the pdp11 back-end. :-) paul

3 years, 1 month

7
12
0 0

Front Panels

by rodsmallwood52＠btinternet.com

Hi ????? I've just done an inventory and I have the following stock ?????? PDP-8/e Type A? Qty 4 ??????? PDP-8/e Type? B Qty 5 ??????? PDP-8/f?????????????? Qty 4 ???????? PDP-8/i?????????????? Qty 8 ???????? New production may not be for a while. Rod Smallwood

3 years, 1 month

1
0
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cctalk Digest, Vol 90, Issue 7 - Re: DEC H500 Digital Computer Lab

by gerhard.kreuzer＠liftoff.at

Hi, I also have an H500 waiting for restoration. Maybe anyone can give better winfos about the plugs/connectors of the patch cables. I didn't have any, I have to make new. With best regards Gerhard Zitat von cctalk-request at classiccmp.org: > Send cctalk mailing list submissions to > ? ? ? ? cctalk at classiccmp.org > > To subscribe or unsubscribe via the World Wide Web, visit > ? ? ? ? http://www.classiccmp.org/mailman/listinfo/cctalk > or, via email, send a message with subject or body 'help' to > ? ? ? ? cctalk-request at classiccmp.org > > You can reach the person managing the list at > ? ? ? ? cctalk-owner at classiccmp.org > > When replying, please edit your Subject line so it is more > specificthan "Re: Contents of cctalk digest..."

3 years, 1 month

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Text art (Was: Found! Ge 115 computer brochure

by cisin＠xenosoft.com

more like this: (Who needs VGA, if you have a non-proportional font?) (Text art, with a proportional font, is psychedelic) ____________________________________ ______________ |------|------| __ __ __ | ___________ | () | | 64X4 | 64X4 | || | | | | | | | | | | ___| |------|------| || | | | | | | |____| |____| || D | | 64X4 | 64X4 | || |__| |__| |__| ________________ ||| I | |------|------| | ________ ______ ______ | ADV476KN50 | ||| P | | 64X4 | 64X4 | |TRIDENT | |______| |______| | 1-54BV 8940 | ||| S | |------|------| || |TVGA | |______| |______| |________________| |||___| | 64X4 | 64X4 | || |8800CS | ________________ ___| |------|------| || |11380029| LOW->| /\ SUPER VGA | _________ | | | 64X4 | 64X4 | -------- BIOS | \/ (1) ||_________| | 1 | |------|------| || ______ J ______ |________________| _________ | 5 | | 64X4 | 64X4 | || |______| 2 |______| ________________ |_________| |___| |------|------| || ________ ______ | /\ SUPER VGA | ___| | 64X4 | 64X4 | |________| |______|| \/ (2) | _________ | | |------|------| () HIGH->|________________| |_________| | 9 | | 64X4 | 64X4 | ________ _________ _____________ _________ | | |______|______|__ |________| |_________| |_____________| |_________| |___| | __ TVGA-1623D _ () | |LLLLLLLLLLLLLL| |LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL| |___| | |

3 years, 1 month

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DECmate II disk image tooling?

by david4602＠gmail.com

I have some disks that look like they're from a DECmate II computer, standard RX50K drives. The disk images all look like they're a mix of 12-bit (OS/78 or OS/278?) and 8-bit all on the same media. I can't convince PUTR to make sense of the images, so I'm wondering if there is anything else out there that is likely to be able to examine the disk contents? I'm really looking for PUTR-like functionality to list and copy files. Maybe SIMH could be configured to be a DECmate II and be fed the disks? I have a couple of disk images available in case anyone wants to try them out - they're purported to be "DECmate II CP/M 2.2 version 2.0" and "System Disk ver. 2.0 8/24/87": https://drive.google.com/drive/folders/1PD0TlUPiT7MIPEX6abEn33e7s3kSXp_H?us… - David

3 years, 1 month

5
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General Data? Computer Equipment Auction - GSA

by skynet＠wans.net

Found an interesting item for bid on GSA auction site if anyone interested. Reminds me of General Data equipment... https://gsaauctions.gov/gsaauctions/aucitsrh/?sl=31QSCI22048010 Sorry, link did not send correctly on first try. Stan Irwin

3 years, 1 month

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General Data? Equipment Auction - GSA

by skynet＠wans.net

Found an interesting item for bid on GSA auction site if anyone interested. Reminds me of General Data equipment... EQUIPMENT RACKS | | | | EQUIPMENT RACKS One lot consisting of: 2 Equipment Racks with the following built in: recorder, processors, disk drive units,... | | | Stan Irwin

3 years, 1 month

1
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Looking for computer and individual to read old floppy disks

by tcoxjoseph＠aol.com

Dear Classic Computers Members,I am looking for someone who had an operating floppy disk drive that can read old 5-1/4" floppy disks from the 1980s.I may also need someone to read hard, 3" floppies.?The disks can be mailed and the info can be saved as text and sent via email or to the Cloud.I would need a price estimate, as well. I live in Virginia.Thank you in advance.Terry Joseph

3 years, 1 month

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DEC H500 Digital Computer Lab

by ccth6600＠gmail.com

As there is no real cctalk traffic other than test messages I thought I post something a bit more interesting. Here is a short video of my fully restored DEC H500 Computer Lab with an 8-bit counter implementation including reset: https://www.youtube.com/watch?v=57xU3Xqnqx4 Enjoy Tom Hunter P.S. Is there some problem with the mailing list? The few "non-test" messages I get are often out of context.

3 years, 1 month

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Found SYSTEM DOCUMENTATION FOR ALUMINUM COMPANY OF AMERICA WARRICK WORKS DATANET -30 REALTIME DATA ACCUMULATOR AND DISTRIBUTOR ... AUG 7 1964

by couryhouse＠aol.com

SYSTEM DOCUMENTATION FOR ALUMINUM COMPANY OF AMERICA WARRICK WORKS DATANET -30 REALTIME DATA ACCUMULATOR AND DISTRIBUTOR ... AUG 7 1964 Sent from the all new AOL app for Android

3 years, 1 month

1
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Digitronics P135-20 Paper Tape Punch

by pbirkel＠gmail.com

I have the mechanism for a Digitronics P135-20 Paper Tape Punch. It turns out that Surplus Sales currently has one of these for sale; see item "(EQP) P135-20/35". It is accompanied by a three-page snippet of a much longer manual for this punch. See: https://www.surplussales.com/equipment/pdf/eqp-p135-20-35.pdf That's the only documentation that I've been able to find :-{. I'd very much like to find/acquire the remainder of this manual, or other relevant documentation. Can anyone help me? Thank you, paul

3 years, 1 month

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testing

by jwest＠classiccmp.org

Test test

3 years, 1 month

5
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RT-11 Kermit to/from a raw device?

by jacob.ritorto＠gmail.com

Is there a way to do this? Or perhaps a driver in RT-11 that I could point to an entire drive? If not, maybe I could write one with some community guidance? Would be a splendid way to write real media, or in my case, read the hundreds of 8" floppies I have sitting on the shelf here for archive. thx jake

3 years, 1 month

2
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PDT-11 Virtual Terminal Monitor v1.07

by lee.gleason＠comcast.net

> and tried looping back pin 2 to pin 3 >on each serial + modem port and typing some characters, but nothing shows >up in vterm. ? PDT-11/150 terminal and printer ports ports all require a high on pin 20, DTR, before they can send characters.? I've never used the modem port on my PDT's but I suspect it requires the typical, pins 6, 8, and 20 wired together. Maybe you need to pull some of these pins high to loop around? -- Lee K. Gleason N5ZMR Control-G Consultants lee.gleason at comcast.net

3 years, 1 month

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Muldivo Digiputer 1968

by silvercreekvalley＠yahoo.com

Spotted on ebay - No involvement in the sale - just tagging in case any one on the list has interest. "Muldivo Digiputer 1968 - Imperial Dialog: IBM Model B" https://www.ebay.co.uk/itm/203849003806

3 years, 1 month

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While on the subject of cabinets...

by chrise＠pobox.com

On Tuesday (03/01/2022 at 04:36PM -0800), Marc Howard via cctech wrote: > I've got a PDP 11/34 I've never opened up. It's mounted in a H9642 > cabinet. I can't get the bloody thing to extend on the chassis track > slides. > > Is there a catch or lock screw on this unit? Mine (and we may be learning, is not be a proper configuration) does not have any release or catch to allow the CPU to slide out. I just grab it and start pulling and it slides out-- although it does not slide easily. That could be due to old, stiffened lubricant on the slides. BUT! make sure you pull out the front foot at the bottom of the rack to keep the whole rack from tipping forward if you do get the CPU to slide out. The CPU is a heavy beast and the rack WILL tip forward once the CPU is out far enough. Chris -- Chris Elmquist

3 years, 2 months

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While on the subject of cabinets...

by pbirkel＠gmail.com

If it's mounted in a standard BA11-K, no. You should be able to pull it out partially (sufficient to tip up if you have rotating slides) and then there should be locking-buttons on the slides to prevent further extension accidentally. Depressing those buttons will allow you to completely remove the chassis and its attached inner slides; the outer slides will remain in the rack. Be careful with full extraction -- the power supply is heavy and the chassis is unbalanced. It's really a two-person operation, or one best accomplished with some sort of supporting mechanism (even wooden cribbing if you are so inclined). If it's anomalously mounted in a BA11-A (like the 11/44) then there is a finger-tab accessible through the front grill on the upper-right that pulls back a spring-loaded side-tab that engages the rack frame to prevent *any* extension whatsoever. Pull that away from the rack-frame and then pull out the chassis. Of course, it's possible that you simply have rusted slides that are binding, in which case you will simply have to use force. Recommend _pushing_ from the rear if "reasonable yanking" from the front isn't working. Although I've encountered a fair share of rusty slides, all have yielded (slowly) to repeated yanking/pushing, even if only a few centimeters at a time. Penetrating oil applied from the sides will help, but after cleaning and polishing the slides suggest that you use graphite or lithium grease to re-lub when reassembling. Others may have alternative lubrication recommendations. -----Original Message----- From: cctech <cctech-bounces at classiccmp.org> On Behalf Of Marc Howard via cctech Sent: Tuesday, March 1, 2022 7:37 PM To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> Subject: While on the subject of cabinets... I've got a PDP 11/34 I've never opened up. It's mounted in a H9642 cabinet. I can't get the bloody thing to extend on the chassis track slides. Is there a catch or lock screw on this unit? Thanks, Marc Howard

3 years, 2 months

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Racking a PDP-11/24

by robert.jarratt＠ntlworld.com

I am wondering if I have racked my 11/24 correctly. As you can see here: https://robs-old-computers.com/2022/02/10/pdp-11-24-progress/ I have put the CPU at the top and the two RL02 drives underneath. The problem is that the CPU enclosure catches on the RL02 underneath. There is a bit of play in the mounting bracket: https://rjarratt.files.wordpress.com/2022/02/cpu-mounting-bracket.jpg. With a bit of manipulation I can get the CPU to slide in. However, I am wondering if I have racked it correctly? I don't think there is room to move the RL02s down and it would presumably leave a bit of a gap below the CPU. There seems to be very little clearance between the CPU and the RL02 at the front but more at the back, but I am sure that the rails are mounted horizontally. Is it just a matter of tightening the big screws that hold the mounting brackets to stop the play? If so I am not sure I have a big enough screwdriver! Regards Rob

3 years, 2 months

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PDT-11 Virtual Terminal Monitor v1.07

by jacob.ritorto＠gmail.com

Hi! Anyone remember how to use this program that announces itself as "PDT-11 Virtual Terminal Monitor v1.07" ? I found it on a floppy of RT-11 v4.0 with my pile of PDT-11 treasures (which amazingly still seem to read fine and work wonderfully; disk file timestamps around 1979 - 1982). I thought maybe it was a term program, since these PDTs were kind of famous for that sort of deployment, and tried looping back pin 2 to pin 3 on each serial + modem port and typing some characters, but nothing shows up in vterm. It does come out of some mode into a command mode, I think, when I send a break to the console. ^C kills it from there and I can get back to RT. I found online a DECUS program of the same name (vterm), submitted by DEC circa 1979, and am wondering if this is the same beastie I've discovered on my 8" floppy: https://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/decus/… ; however, when I try to click through that decus website, the actual packages themselves seem to have been lost! Does anyone know where to obtain the actual files that came with this 110417 from DECUS? And if I'm on the right track, here? It would be cool to have this PDT-11 functioning as God intended if this vterm is actually a terminal emulator type of thing... thx jake

3 years, 2 months

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Tandon TM 848-02

by bill.gunshannon＠hotmail.com

Does anyone have anything on the jumper settings for this drive? I would like to jumper it so it can read DEC RX01/RX02 floppies. I am looking at being able to read disks on a non-DEC systems but I would also like to be able to use it on my Andromeda card in a real PDP-11. bill

3 years, 2 months

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RQDX3/RD31/RX50 jumpers

by rodsmallwood52＠btinternet.com

Hi ????? Is the correct setting: ?????? 1. DS1 on the RD31 and the RX50's move up to DU1 and DU2. ?????? 2. DS3 on the RD31 and the RX50's are DU0 and DU1 I've tried both and it still? tries to access the RD31 and the RX50 at the same time. Its on a standrd BA23 R

3 years, 2 months

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Is The M9312 Boot Module Essential?

by jnc＠mercury.lcs.mit.edu

>> (I have yet to check and see if the KY11-LB asserts SACK if the CPU >> halts on its own accord - probably 'yes', but that's a project for tomorrow.) Yes, it does. I toggled in the following program: 5000 5200 776 0 (what, you all can't program a PDP-11 in octal? :-) and hit 'start' and the SACK light on the UA11 flashed out and came back on when the machine finally halted. So then I looked at CPU tech manual for the KD11-E, and the HALT instruction seems to act exactly like the console has requested a processor halt; it just sets the HLT RQST signal (see Section 4.5.5 "Operate Instructions"). So, either (console halt, or a HALT instruction) will cause the identical response in the processor; see Section 4.10.3 "Halt Grant Requests": the CPU sends HLT GRANT to the console, which returns SACK. As long as SACK is asserted, the processor waits with its clock inhibited: "The user can maintain the processor in this inactive state (Halted) indefinitely. When the HALT switch is released, the user's console releases BUS SACK L, and the processor continues operation" This text is obviously for the KY11-LA; the KY11-LB will operate identically: when the console releases SACK, the processor resumes operation. > From: Fritz Mueller >> when I powered the machine on, it turned out that something was >> asserting SACK when the machine was halted > That is quite interesting, and not what I would have expected! Yes, I was quite surprised; I didn't expect that either. Now that I know that the KY11-LB uses it to talk to the KD11, I can work around it, though. I'll have to write all this up to warn others about it. >> The thing that's puzzling me is that the M8264 seems to exactly >> replicate the functionality of the M9302, with an 'unused' bus grant >> being turned into a SACK. So I don't understand the point of the M8264. > I think the only difference would be that since the M8264 is timer > based, it doesn't need the intact end-to-end path required for > turnaround. So your bus won't lock even if you have a broken grant > chain or a poorly behaved or hung device eating grants. You are right about it being timer-based, but I'm not sure the conclusion follows, at least exactly as stated. If there's a broken grant chain, then as you originally pointed out, the M9302 will jam SACK on. The M8264 could not even be there, and nothing would be any different. Same thing if the CPU asserts a grant in response to a now-removed interrupt request: the M9302 will jam SACK on, etc, etc. I'm racking my brain to think up _any_ circumstance in which the M8264 will assert SACK. in which the M9302 wouldn't. Thinking it through, there has to be a grant, but it can't get to the M9302 (because otherwise it would do its thing), but that failure to get there can't be simply a broken grant chain (ditto). So some device has to be malfunctioning: not passing a grant along, but eating it. So either a hard-failed component in the grant-passing circuit, or some design flaw. (It can't be a glitch; it has to be a permanent thing which prevents passing the grant.) I suppose that's possible, but I can't see any othey way. Noel

3 years, 2 months

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Is The M9312 Boot Module Essential?

by jnc＠mercury.lcs.mit.edu

First, a minor correction: > the M8264 Sack Timeout module ... there's next to nothing in print > about them There is also some coverage in EK-KD11E-TM-001, at: Section 4.7.2.4 "M8264 NO-SACK Timeout Module" (pg. 4-41, pg. 87 of the PDF), which I found while looking for parity stuff (below). > From: Fritz Mueller > The KD11-E is pretty bare boned... Parity handling was also a quad "add on". ??? The KD11-E/EA doesn't do much with parity (below), so at first I thought that maybe you were thinking of the M7850 Parity Controller (which is actually a memory option, not KD11-E/EA specific; more below), but that's a dual card. The KD11-E/EA does not (like most PDP-11's) calculate parity; PDP-11 memory units do all the work, and signal 'parity error detected' to the CPU over the UNIBUS (using the PB line); the CPU will trap when it sees that (if enabled; the KD11-E and -EA can disable recognition of parity errors, with jumpers). See Section 4.7.2.7, "Parity Errors", in EK-KD11E-TM-001 (at pg. 4-45, pg. 91 of the PDF); the circuit diagram is on page K2-1 of the KD11-E/EA FMPS. The M7850 has to be in the same backplane as the memory, but that can be a different backplane from the one holding the CPU. So it can be 15' away, at the other end of a UNIBUS cable. Anyway, can you say more about the parity add-on? >> So if i) a device requests a grant, and then drops the request at >> _just_ the right time ... and ii) there's a break in that grant line >> ... before it gets to the M9302, which can turn it around as a SACK , >> then ... the KD11-E CPU will hang! > I believe a broken grant chain with an M9302 in place on the far side > results in the grant being pulled up at the M9302, and then continuous > assertion of SACK, hanging the processor straight out the gate. Oh, right you are! (I'm glad _your_ brain is runed on - unlike mine! :-) I happen to have an -11/04 (the -11/34's sibling) on the bench in my work room, with one of Guy's very useful UA11's plugged into it. (BTW, the UA11: http://www.shiresoft.com/products/ua11/Unibus%20Analyzer.html is fantastically useful as a UNIBUS debugging tool. Everyone working on UNIBUS machines should have one.) So I thought I'd go try an experiment. It turned out to be a bit more complicated than I thought, but you're basically right: a break in the grant lines (e.g. missing grant continuity card) causes the downstream card to 'see' 'phantom' incoming grants (open TTL inputs float high), and signal a grant on from there; and if there's an M9302 at the end of the bus, it will see that and jam SACK on. The complication was that when I powered the machine on, it turned out that something was asserting SACK when the machine was halted; if I put it into a 'BR .' loop, that goes away. I looked, and the KD11-D doesn't even _have_ a SACK driver! So I tried un-plugging the KY11-LB, and the 'SACK on halt' went away. (That machine has core, and I set the power-on vector to halt the machine.) Looking at the KY11-LB manual, it does in fact assert SACK (after it has sent the KD11 a 'halt request, and receives a 'halt acknowledge'), to recognize the CPU's acknowledgement of the halt request. (I have yet to check and see if the KY11-LB asserts SACK if the CPU halts on its own accord - probably 'yes', but that's a project for tomorrow.) The thing that's puzzling me is that the M8264 seems to exactly replicate the functionality of the M9302, with an 'unused' bus grant being turned into a SACK. So I don't understand the point of the M8264. Whether the cause of the grant is a rare timing window of a bus request being cancelled, or a broken grant line; with an M9302 in the system, a SACK will result. The only difference between the two is that because of the way grant lines are wired, the M8264 will not respond to a broken grant line 'downstream' of the M8264. The M8264 does add this capability to a system using an M930 terminator - but just switching to an M902 would be simpler. And the M9302 pre-dates the M8264, as we can see from EK-11034-OP-PRE2. So I'm really quite confused as to what the point of the M8264 was. Noel

3 years, 2 months

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Is The M9312 Boot Module Essential?

by jnc＠mercury.lcs.mit.edu

> From: Mattis Lind > What about the M9300 board? Do you have an idea what the purpose is of > that card? Yes, that one's well-documented and understood. It's intended for use on the 'B' UNIBUS of the RH11-AB, in deployment configuratons where that UNIBUS is in use, but there's no CPU on it to respond to NPR bus requests. (See: http://www.bitsavers.org/pdf/dec/unibus/RH11_Peripheral_Controller_Course.p… pg. 11 for an example; the 'B' UNIBUS of the -11/45 is used for a separate path into the 45's dual-port FASTBUS memory.) On such a UNIBUS, the M9300 is used at the start of the bus, and is jumpered to allow on-board circuitry to respond to an NPR with an NPG.It also has a SACK timeout capability, documented in: http://www.bitsavers.org/pdf/dec/unibus/RH11-AB_OptionDescr.pdf on pp. 69-70, but I'm not fully familiar with that. Noel

3 years, 2 months

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Is The M9312 Boot Module Essential?

by jnc＠mercury.lcs.mit.edu

>> On Feb 19, 2022, at 10:51 AM, Noel Chiappa wrote: >> The -11/34 (not the /34A) has something unusual for grant timeouts, >> but I forget the details. I'll look it up. And here it is... > From: Fritz Mueller > I think you are thinking of the M9302, Noel: a far-side terminator card > with integrated SACK turnaround? No; the M8264 Sack Timeout module. What's an M8264, you say? Well, there's next to nothing in print about them, but I think I've managed to assemble enough distant clues to work out their story. Start with EK-11034-OP-PRE2 (I have a hard-copy of it); it gives a clue as to how it all started. In 3.10.2, "End-of-Bus Terminator", it says: "As a result of this [SACK turnaround] circuitry [on the M9302], the SACK timeout feature found on other processors is not required" So if i) a device requests a grant, and then drops the request at _just_ the right time (so a grant gets sent out when there's no device waiting to grab it), and ii) there's a break in that grant line (maybe a missing grant continuity card) before it gets to the M9302, which can turn it around as a SACK , then ... the KD11-E CPU will hang! The M8264 was apparently the first attempt to deal with this. Like I said, there's next to nothing in print about them. EK-11034-UG-001, in Section 1.2, "System Description", does list "M8264 SACK Timeout module (11/34 only)" in the list of components - but says nothing else _at all_ about it! There is one page of circuit diagram of it, in: http://www.bitsavers.org/pdf/dec/pdp11/1134/MP00082_1134_Vol2_Sep76.pdf on pg. 149. The rest of the prints for it (e.g. the PCB layout) aren't there, but I happen to have one - it's a quad board with only a few components on it. Looking at the circuit diagram, it's mostly just a 9602 retriggerable, resettable one shot. (There's also a synchronous 4-bit up/down counter, but that's just there to count events, and display the count in some LEDs - probably just to make sure it isn't happening too often.) Since I'm not a real hardware type, I'm not absolutely certain just from looking at the circuit diagram exactly what it does, or how, but EK-KD1EA-MM-001 Section 4.7.2.4, "No-SACK Timeout Circuitry", shows a very similar circuit, and says it "asserts BUS SACK ... [if the device] does not assert SACK within 22 usec after a grant line has been enabled." Presumably the M8264 does the same thing. Interestingly, that circuit appears in the KD11-EA prints on pg. K2-10; the KD11-E prints have a blank space on that page where this circuit is in the KD11-EA prints. Since the M9302 appears in EK-11034-OP-PRE2, with SACK turnaround, I deduce that the M8264 was produced _after_ that came out, and post-dates the M9302, to fix the potential CPU hang issue I described - and was later dropped when the -11/34 switched to the KD11-EA, with that circuit built in. I'll do a page on the CHWiki about the M8264, and include an image of one. I figure I might use my M8264 on my -11/04, which also doesn't have SACK timeout (on the BG lines, for sure; it looks like it might have it on the NPG line). The M8264 doesn't tie into the CPU, it just looks at UNIBUS lines, so it can be plugged into any UNIBUS machine (near the start of the bus, since the grant lines it monitors are wired sequentially). Noel

3 years, 2 months

3
3
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Information about an unknown IC

by clemarjr＠gmail.com

Hi I'm looking for information about Texas Instruments TB-759933 IC. Does anyone have the datasheet or any other information about this IC? Thanks.

3 years, 2 months

9
14
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Seeking paper tape punch

by fedorkow＠mit.edu

hi Steve, ? There's lots of raw material out there.? Al Kossow read hundreds of tapes a couple years ago, and posted the images at http://www.bitsavers.org/bits/MIT/whirlwind/X4222.2008_Whirlwind_ptp/ ? Whirlwind and modern readers disagree on what order the bits come in, but other than that, the files are perfectly usable.? We have some of the programs running in simulation, as you've seen. ? The Whirlwind tapes in the archive are all seven-level tapes punched on 7/8" paper. ? Let me know if there's something I can help with /guy Date: Tue, 22 Feb 2022 12:24:18 +1000 From:steven at malikoff.com To: "ben"<bfranchuk at jetnet.ab.ca>, "General Discussion: On-Topic and Off-Topic Posts"<cctalk at classiccmp.org> Subject: Re: Seeking paper tape punch Message-ID: <78ae9afacbca8b3ca7e7a41c677659d0.squirrel at webmail04.register.com> Content-Type: text/plain;charset=utf-8 Ben said > This requires a REAL MACHINE SHOP ... none this 3d printer stuff. I > would recommend a building a 35mm film punch and reader, as film stock > is still easy to find compared to paper tape. Zuse used them for his > computers in Germany on the 40's. Quality Mechanical stuff is lost high > tech. Consumer-grade CNC stencil cutters are fine at cutting plastic sheet and should be ok with film stock. My ptap2dxf (latest version 1.3) will produce output to cut tapes for 8-level ASCII, 5-level Baudot, 2-level Morse (Wheatstone and Cable Code), 7-level Whirlwind, Teletype Chadless and some customising options too. Still some other formats to do such as Colossus etc. Thanks for the notion of making Zuse tape, will look into it. Steve.

3 years, 2 months

1
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11/83 operating system load update -2

by rodsmallwood52＠btinternet.com

Hi ?? Well I have had a huge response to my request. I am unsure as to if I have defined the problem properly. So a few bullet points. 1. The objective is to copy RX50 disk images (*.dsk format) to genuine DEC RX50 disks. 2. The PC I want to use is a DEC Celeibris FX ie the PC and its W95 software is as supplied by DEC. 3. It has an RX33 5.25 inch floppy drive. 4. The RX33 _*is*_ capable of? reading and writing RX50 disks. 5.? putR was supposed to be able to do this. It does not. 6.? All that is lacking is the right utility. 7. Doing this does not need any disks other than RX50's. 8. Linux in any of its myriad of forms is not the answer. 9. simH is good at what it does but of no use here 10.? Its just a W95 utility program to copy an RX50 disk image to an RX50 disk on an RX33 drive on a DEC PC. 11. So whats it called? Does it work? given the above situation? Rod

3 years, 2 months

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11/83 OS load - problem solved.

by rodsmallwood52＠btinternet.com

Hi ???? Well I now have a full set of DEC orignal MicroRSX RX50 distribution disks. An old friend who I worked with at DEC had kept his install go bag and there they where. Not only that they are good and do boot. Its not over, RT-11 would be a better fit so I'm looking at that. Rod

3 years, 2 months

2
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DEC VT52 CRT anode connection

by fritzm＠fritzm.org

Hi folks, I?ve begun some work on a VT52, and need to get the power supply board out onto my bench for some work. For those who have been in here before: is there a way to detach the HV anode lead at the board side (does the white ?cap? come off the lead connector?) Or is the only option to unclip at the CRT itself? They don?t make it easy to get to the anode cap in this terminal ? one has to pull the whole tube, with the power supply board in tow. After doing this for an inspection, I find the anode cap looking little brittle and covered with some red, oily ?goop?? I?d rather just leave that alone and detach from the board side if it works that way? cheers, ?FritzM.

3 years, 2 months

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Speaking of tubes in computers.... 1st Honeywell 1000 computer used some surprise tubes!

by couryhouse＠aol.com

Speaking of? tubes in computers.... 1st Honeywell 1000 computer used some surprise tubes!? ??Imagine our surprise back then as? we unpacked our? first? group of? contributed Honeywell 1000 logic and saw....? LOCTAL TUBES!?Although SMECC does not? have? a complete Honeywell system of? this model? (CPU and? PS would? weigh in at 25,000 pounds? we have been told)? We DO possess? a wonderful collection? of documentation, parts? and? misc.? material related? to it, perhaps one of the best. Who else has some? We? used? to? think our 2 inch QUAD? videotape was a monster reel of? tape...BUT? WAIT!The First Honeywell Computer used 3 Inch Wide Tape! It was like mounting a Volkswagen Tire Wheel onto your computer tape drive! Channels or tracks on the tape... 31 Channels ?ALWAYS LOOKING? FOR MORE RELATED TO THIS COMPUTER!? See more info on this computer at: http://www.smecc.org/honeywell_datamatic_1000.htm drop me a note at? couryhouse at aol.com?

3 years, 2 months

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cctalk Digest, Vol 89, Issue 21

by athornton＠gmail.com

The 11/83 question sounds like a job for SCSI2SD to me. Install a system with simh. dd the resulting disk image to your sd card. Hook the SCSI2SD up to your 11/83 and boot from the card. Copy the contents of that drive to your real SCSI drive. Done. SCSI2SD cards are not expensive and are a tremendous value for money.

3 years, 2 months

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'dd' for Windoze (Was: cctalk Digest, Vol 89, Issue 21)

by jnc＠mercury.lcs.mit.edu

> From: Rod Smallwood > dd is a linux command. UNIX, actually. (V5, I think: https://minnie.tuhs.org/cgi-bin/utree.pl?file=V5/usr/source/s1/dd.c There no 'man'page for it in V4. Anyway...) > I only have windows PC's. There are Windoze versions. I've used this one: http://www.chrysocome.net/dd with success (under XP; probably works under others, too). Noel

3 years, 2 months

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