test-drb February 2015

test-drb@ccmp.vtda.org

203 participants
261 discussions

by rickb＠bensene.com

There is a Fry's in Wilsonville, Oregon -- They've already expanded out of "the valley". -Rick > -----Original Message----- > From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Bill > Sudbrink > Sent: Friday, February 06, 2015 11:59 AM > To: 'General Discussion: On-Topic and Off-Topic Posts' > Subject: Fry's expansion? was: RE: Radio Shack > > Marc Verdiell wrote: > > Here in the Valley, Fry's Electronics took over, and then made it so > > much better. Fry's is where you stop at lunch time, for amateur or > > professional stuff alike, and get an instant replacement for your > > fried LM7805. > > A few years ago, there was a rumor that Fry's was going to expand out of the > Valley. I wonder whether that might happen now that RS is on its way out. > > Bill S.

9 years, 4 months

It's time to restore the 11/45 - progress!

by jnc＠mercury.lcs.mit.edu

> From: Jacob Ritorto > I guess this crowbar thing tripping, is just its way of trying to > protect the rest of the system from overcurrent, right? Over-voltage. Voltage != current. :-) > And the dried up cap is one thing what could make it think there was an > overcurrent situation, correct? I think the concept is that the cap could have shorted out, thereby causing a too-high voltage to pass through it - or something like that! :-) In general, cause the circuit to mis-behave. > I don't know that I'm going to understand how to read the schematic. I struggle with the analog circuits too. Just keep plugging away at it, each will slowly start to make sense. (Not the most complicated/sophisticated aspects, but if you understand a lot of what's going on, I'm sure someone here can help on the tricky bits.) > Also going to try to find a manual that describes the power supply. DEC's maintainence/technical manuals are very good indeed for explaining how the analog circuits work - especially for those of us who can't just glance at a schematic and instantly, intuitively understand how the whole thing works. For me, reading them is really pretty much a must before trying to debug/repair analog stuff. > But what is a valid test once I find it? This is where you need test instruments; an ESR meter (although that's not a universal solvent), a capacitance meter, etc, etc. (Also an ohmmeter, to check for shorted caps.) > I don't have much electronics gear here. If you seriously expect to repair something like an 11/45, at a _minimum_ you need a decent 'scope. Don't even _try_ thinking you can do it without one. Fuhgeddaboutit. I like Tektronix 465's - they are common on eBay, and if you're patient, you can get one for $60-70. They are also a 'scope much used on these machines BITD. (We did.) Past that? Well, there are things that are nice to have (e.g. a de-soldering station), but you can often work around them (e.g. a pair of dikes and a solder sucker). A logic analyser would be nice, and I keep meaning to get one, but I haven't, yet, so they aren't essential. (Although for _some_ faults, a 'scope just doesn't cut it. If you can write a loop, fine. If not... time for a logic analyzer.) I'm trying to think what else is absolutely essential, past the 'scope (and the meter - you ought to buy your own, they aren't that much). Nothing comes to mind immediately - perhaps someone else here can add to the list. Noel

9 years, 4 months

Remember Coherent?

by lproven＠gmail.com

I could never afford it & figured I wouldn't understand it if I did. But it sounded really cool. Well, as of last month, it's now FOSS. http://www.nesssoftware.com/home/mwc/source.php -- Liam Proven ? Profile: http://lproven.livejournal.com/profile Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven MSN: lproven at hotmail.com ? Skype/AIM/Yahoo/LinkedIn: liamproven Cell/Mobiles: +44 7939-087884 (UK) ? +420 702 829 053 (?R)

9 years, 4 months

DEC MKA11 and/or M8261/M8163

by pbirkel＠gmail.com

I don't understand the role of the M8162 "Port MUX A module" and M8163 "Port MUX B module" that the field-guide claims to be part of the MK11. They aren't part of the MK11 as far as any documentation that I've read regarding it. At least the M8162 has a pair of 20ma-style SLU connectors on it, but no UARTs that I can see. Do these modules really belong to the MKA11, rather than the MK11? Or to something else entirely? Is the MKA11 (which I can't find documented online) a revised MK11? The field-guide seems to imply this given its entry for the M8164 which basically reads like this: M8158 MK11 U Address buffer module M8159 MK11 U Data buffer module M8160 MK11 U Control A module M8161 MK11 U Control B module M8162 MK11 U Port MUX A module M8163 MK11 U Port MUX B module M8164 MK11/MKA11 U Data buffer module (Replaces M8159) It seems to me that something is incorrect in the field-guide, but none of my researches have identified where the error is and what the right answer(s) might be. Anyone here have any experience/knowledge with/of the MKA11 and/or the M8261/M8163? Thank you, paul

9 years, 4 months

ISA ( PC ) 8" floppy disk CONTROLLER ???

by gerardcjat＠free.fr

Thanks Shaun !! If you find the interface card and associated documentation, I would be interested. Please, let me know My philosophy : DBIT adapter is probably a very good product ..... but If I can stand with ** genuine ** "old stuff", I would love it . --- L'absence de virus dans ce courrier ?lectronique a ?t? v?rifi?e par le logiciel antivirus Avast. http://www.avast.com

9 years, 4 months

It's time to restore the 11/45.

by jnc＠mercury.lcs.mit.edu

> From: Jacob Ritorto > Can anyone understand and explain the unibus a / unibus b concept? I've never personally worked on a machine with them separate, but the picture on pg. 15 of the 11/45 Processor Handbook (1971 edition), and accompanying text, should make what's going on pretty clear. You have the 'normal' UNIBUS ("UNIBUS 1" they call it), controlled by the 11/45 CPU, on which regular memory, devices, etc live. The CPU also has access, via a special path (I guess this was later named "FASTBUS"?), to two _separate_ banks of high-speed memory. Those memories are _each_ dual ported; one port to the CPU's direct path, the other to a second UNIBUS, ("UNIBUS 2"). So something on UNIBUS 2 could be talking to one bank of high-speed memory while the 11/45 CPU talks to the other bank - while at the same time, a DMA device on UNIBUS 1 could be talking to memory on UNIBUS 1. I.e. three separate memory transfers all going on _completely_ simultaneously. UNIBUS 2 does not have a 'bus master' - one has to be provided by plugging some PDP-11 into it. One can either plug another PDP-11 into UNIBUS 2 (forming a primitive multi-processor, one in which the two machines share access to the high-speed memory on the 11/45); or one can 'jumper' the two UNIBI (is that the plural?) in the 11/45 together, at which point DMA devices on UNIBUS 1 can do DMA into the high-speed memories (which they do not have access to, if the two are separate). The way grants, etc, work is pretty simple. (You can skip this part if you don't care about the really gory details. :-) UNIBUS connectors include BGn and NPG - in at one end of the cable/jumper, out at the other. So that short section of UNIBUS 2 (it's actually just a chunk of the 11/45's main backplane) can either have: - a pair of UNIBUS cables (one in, one out) to make it part of some other machine's UNIBUS; - one UNIBUS cables (in), and a terminator at the other end, to make it the last thing on that machine's UNIBUS; - a UNIBUS jumpers (in) to make it part of the 11/45's UNIBUS, with the 'out' UNIBUS connector on UNIBUS 2 leading to the rest of the 11/45's UNIBUS If you don't jumper UNIBI 1 and 2 together, the 'UNIBUS out' cable to the rest of the 11/45's UNIBUS is plugged straight into the CPU's 'UNIBUS out' slot (i.e. where the jumper would have plugged in if the two UNIBI were united). > Should I eliminate all this fancy bipolar and core memory and just use > an m7891? For debugging, yes; simplest is always best. But if you have the fancy bipolar or MOS (not core; the fast memory path only supports the first two), don't pitch it, it's probably rare and unusual; and once you have the machine running, you may want to play with getting it running. > If I did, would it be on the fastbus, unibus a or unibus b and would it > even matter? Has to be on UNIBUS 1. (UNIBUS 2 becomes part of UNIBUS 1 if the two segments are jumpered together.) Noel

9 years, 4 months

11/23 clock issue

by jnc＠mercury.lcs.mit.edu

> From: Holm Tiffe > Hmm.. it looks to me as if the Board is missing the jumper W1 Err..... no. :-) Noel

9 years, 4 months

Incandescent lights [Re: It's time to restore the 11/45.]

by jnc＠mercury.lcs.mit.edu

> From: John Kaur > If anyone has worked up a led replacement for the '45, would be of > interest. The original incandescents are not easy to find 'Back in the day', there were LED replacements available - I have no idea who from. They looked just like the bulbs, but had the red glass. (We replaced all the lights in our 11/45 with them.) Anyone know who/where/what they were? Or of a modern equivalent? Noel

9 years, 4 months

DEC fan silliness

by roeapeterson＠gmail.com

So I've got a BA11-N chassis (18-bit, 9xQ-cd slots) and the cardcage fan has failed. The damn thing is riveted in, I'm gonna have to drill. Strangely, the power supply fan has bolts/nuts. I've never seen DEC do something this silly before, but I'm sure there are stories out there...

9 years, 4 months

It's time to restore the 11/45.

by jacob.ritorto＠gmail.com

Hi, Having gotten the 11/34 rig up to a good spec, I'm sufficiently excited to tackle the 11/45. It's been powered off since 2004, when I briefly turned it on only to find a wild jumble of lights and that none of the front panel switches or knobs did anything to the lights. Couldn't get it to run or deposit values or *anything*. I therefore assumed it was badly broken and so left it until now. It has stayed perfectly high and dry but has gone to extremes in temperature as the storage isn't climate controlled (this is in western Pennsylvania). And there's a lot of dust. I'm not going for museum perfection, but want it to be very presentable (lobbying to keep it as my 'art' in the living room long term if it's presentable enough :) and functional. So I'm looking for tips on how to go about it? I was thinking: 1) Truck machine to living room, note positions of all wires / boards. Photograph, remove and clean dust from them. Place on antistatic bench. 2) Thoroughly blow out dust and debris, vacuum backplane and wipe down chassis and wires with damp cloth. 3) Map out desired hardware config: I have available two Fujitsu 160 disks, three Fujitsu M2333K disks and two Fujitsu M2372K disks. I need to decide how to rack and cable at least two, possibly up to four of them as the 8" ones have no mounting hardware. Operational status on all is "hopeful." I have two Emulex SC21s and an SC41 as well as an unmarked Xylogics Unibus SMD board. I'm also tempted to mount an RX02 drive as I have a controller and quite a mountain of floppies supposedly containing weird old stuff. I need to source an ethernet board and whatever cabling / bulkhead stuff follows. DZ11, its dist panel and a Diablo 630 printer would be nice, too. 4) This would also be a good time to broach the subject of whether or not the capacitors need special love, or if that just adds more risk of destroying something. Those familiar, please chime in as the archive is currently missing so I can't refer to the recent threads on this subject. Datapoint: I didn't mess at all with power supply / caps on my 11/34, which was stored right beside the '45 for the same timespan and it's running great now. Datapoint 2: with my amateur electronics skills / status, there's admittedly some risk just having me poking around in there, "learning" things :-\ Plus, I'm afraid of death from esoteric high voltages that I hear are present in these old power supplies. Is the 11/45 one of them? In a nutshell, this analog / power stuff is FAR FROM my forte; some hand-holding here would be most appreciated. 5) Insert an expendable Unibus module and power up; check & tune power. I need direction on how to go about this. Also, the bottom H742A power chassis isn't completely populated. Not sure if that's acceptable, on purpose or bad. 6) Reassemble, tidying up issues like missing / loose screws, rubbing cables, etc. along the way. 7) rt, 2.11BSD, rsx, rsts/e! (mostly via vtserver - I have a tu10 that I could get in on this deal, but its roller rubber has turned into goo and two cabinets in the living room is more than "pushing it." Later date on that puppy. ) Current module config starting from front of cabinet (yes, there are some gaps and M9200 jumpers I don't mention, too): M9301 + M787 M8114 M8115 M8112 M8113 M8100 M8101 M8102 M8103 M8104 M8105 M8106 M8108 M8107 M8109 M8110 g401 M7800 + M9200 jumper H214 G231 G110 H214 G231 G110 H214 G231 G110 Unibus cable runs out to third party external memory chassis, "Monolithic Systems Corp" Type MO v11/PDP11 P/N 300-0058-000, which is three quarters populated. If this memory is broken, I'm planning to use an M7891 instead (is that OK?). No Unibus termination after that. Is that weird / bad? Does this current config seem sound? Is there a problem obvious just from this description that would account for the unresponsive front panel? Here's the power supply situation: There are two H742A power chassis. Top contains h744, h744, h744, h744, h745. Bottom contains H745, H746, open, H744, open. big thx! jake

9 years, 4 months

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test-drb February 2015