test-drb

test-drb@ccmp.vtda.org

101090 discussions

by silvercreekvalley＠yahoo.com

Hi - does anyone have any spare Sun 'sledges' for the older pizza-box style Sparcstations? These are used to mount the hard-drives in the box. Thanks. Ian.

17 years, 3 months

Powering up a 20-year old MicroVAX II

by doc＠mdrconsult.com

Robert Jarratt wrote: > After removing all the boards and leaving just the disk and tape drive for > load I impetuously decided to try powering it up. I knew the PSU (model > H7864) was set for 110V and made the switch to 240V (I am in the UK). When I > connected the power cord, after a few moments there was a loud pop, followed > by another before I could pull out the power cord, smoke rose from the PSU. > This sounded just like when I had once accidentally made a 110/240 mix-up. > > The question is, could it be that I had not made the switch to 240 > correctly, or could this just be down to the age of the PSU? I haven't been into a BA23 PSU, so this is a question, not a suggestion - does that PSU have a separate "jumper" plug for 50Hz/60Hz switch? I toasted an RA60 once by just flipping the visible switch from 240V to 110V, not knowing there was a separate physical setting to switch it >from 50Hz to 60Hz. The behavior as it burnt up was just like this. Doc

17 years, 3 months

Electrolytics

by tshoppa＠wmata.com

Will writes: > So even though I was one of the first people on this list > to suggest reforming old capacitors, I have basically > completely reversed my view > on the issue. Now, if the machine is not super old, I will > just pretty much plug in the machine and let it power up. > Even if something does fail, most of the machines I > deal with have enough built in protection > that they will just shut down safely. Some of us do the opposite of using a variac to reform caps - we use a variac to stress-test the components at above the rated voltage. If they blow up now, that's better than them blowing up later. We always called this "margining". I suppose it depends on attitude. To some people a KA630 in a BA123 is a holy shrine to be babied all the way back to restoration. Which I find odd, because there isn't that much that's actually restorable. I mean, 20 years ago I was fixing rubber bumpers in RD53, but who today wants to go through that much work for 70 Mbytes of really slow storage? Maybe I just hate all those stupid MFM drives too much. Tim.

17 years, 3 months

Electrolytics

by jgessling＠yahoo.com

> We always called this "margining". Years ago, I had read a book about the Whirlwind computer developed at MIT. In that book was the claim that margining had been invented during that project, the idea being to increase the voltage and make the weak tubes fail so that overall reliability would be improved after they were replaced. I've wondered if that's really true or was the technique in common practice and it just became formallized at that time and entered into historical lore. Of course Whirlwind was also important for other developments like core memory and employing a young grad student by the name of Ken Olson. BTW, I think the book was: Project Whirlwind: History of a Pioneer Computer by Kent C. Redmond, Thomas M. Smith Digital Press, 1980. Definitely a good read, alas, my copy is miles away. Regards, Jim

17 years, 3 months

AAARRGGGHHHH ... people still stealing my work

by evan＠snarc.net

This was an issue a couple of years ago. Now it's back: the 10,000-word article that I published on my personal web site in 2005 (and since took down) is reprint IN FULL at http://www.iranianpda.com/iPDADB/FAQs/PDAHistory/ThehistoryofPDAs.htm, obviously without my permission. Whatever moron did this even included my disclaimer saying not to steal my work!!! Here are two other examples: Big yellow chart 1/3 down the page: http://um_pxgt_6103.seedwiki.com/wiki/um_pxgt_6103/pda_-_discuss?wikiPageId= 237424 Timeline 1/4 down the page: http://pdaforum.ladoshki.com/viewtopic.php?t=20027 <http://pdaforum.ladoshki.com/viewtopic.php?t=20027&postdays=0&postorder=asc &start=5&sid=772e87081af243f1c20a6cc14bb989ce> &postdays=0&postorder=asc&start=5&sid=772e87081af243f1c20a6cc14bb989ce Can anyone help?

17 years, 3 months

Why Do the OOP Seller's Use RFQ?;Was: Source for bipolar PROMs?

by trag＠io.com

> Date: Mon, 23 Feb 2009 21:03:22 -0500 (EST) > From: Steven Hirsch <snhirsch at gmail.com> > The 571 seems to be pure unobtanium, unless you > count 50 hits of *&ssholes who want you to submit an RFQ and won't deal > under $250 a shot. Does anyone know why those businesses operate that way? Why not just post a price list? A line item on their RFQs is always "Target Price". Well, honestly, my target price is 0, of course. I know I won't hit it, but that's what I'd like. I'm certainly not interested in telling them there is a floor to the price they can offer me. And how is it more profitable to them to let this stuff sit in (costly) storage somewhere, rather than selling fifty pieces to someone who could use them? I've been hunting WD92C32 for a long while and they all seem to be in the hands of *those* people. About once a year I do another search, and the quantity available listings never change. There's plenty of them out there, doing nothing, but try getting your hands on any for less than $5 each. The total value of the thing I want to build is probably $15 so spending $5 on one component is ridiculous. Jeff Walther

17 years, 3 months

RL02's And RL01 Offered Baltimore Maryland

by fsmith＠ladylinux.com

Hi, I have two nice RL02's and a RL01 I am offering either for trade or whatever to whom ever wants to stop by and pick these up. They were part of a E-Pay lot I bought over a year ago and were working when deinstalled. I am looking for a later BA23 case with skins (Hopefully) so I can build my frankenpdp with or anything else including good beer you want to offer. I had to haul them here and store them so something must be offered but I am not asking for much. No shipping as they just are too big. More stuff is coming to be offered up as I have discovered a old love with vintage audio equipment and some of my Dec "Projects" have to be put into the hands of people who will actually use them. -- Kindest Regards, "No Problems Only Solutions" L.B. Network Consultants LLC. Baltimore, Maryland

17 years, 3 months

VCF's this year

by rborsuk＠colourfull.com

Hi All, Has there been any dates for VCF's this year? Rob Rob Borsuk email: rborsuk at colourfull.com Colourfull Creations Web: http://www.colourfull.com

17 years, 3 months

Central Point Option Boards available

by trixter＠oldskool.org

I've seen a smattering of interest around Option Boards in this list every few months, so I thought I'd mention that my last two option boards are now up for auction, an older CopyIIPC Option Board and a Deluxe Option Board: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110355365098 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110355371748 I set the starting prices at about half what I've seen them go for in the past (and that was for loose boards). -- Jim Leonard (trixter at oldskool.org) http://www.oldskool.org/ Help our electronic games project: http://www.mobygames.com/ Or check out some trippy MindCandy at http://www.mindcandydvd.com/ A child borne of the home computer wars: http://trixter.wordpress.com/

17 years, 3 months

8088 vs. 80c88

by ajp166＠bellatlantic.net

> >Subject: Re: 8088 vs. 80c88 > From: "Chuck Guzis" <cclist at sydex.com> > Date: Tue, 24 Feb 2009 03:29:14 -0800 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 23 Feb 2009 at 18:36, Allison wrote: > >> That it had bugs, can't argue that. They could have just as easily given >> it the base uCOM78 instruction set instead. But how many V20s were bought >> to run 8080 rather than as a faster varient of the 8088? > >To be certain, almost all of the publications that I saw touting the >V-series chip emphasized the performace aspect. Few even mentioned >the 8080 emulation mode. I was surprised to see emulation extend to >the V40 and V50 uPs. > >And almost none mentioned that the V20 implemented many of the 80186 >and some of the 80286 instructions. > There was that too. >I've heard reports where the V20 doesn't work as a drop-in >replacement for an 8080. Must be just enough timing difference that >one works and the other doesn't. > True also. the original IBM PC didn't run it, as well as any cpu other than intel. Seems there was a minor timing issue that the intel part tolerent of but no one elses would work.. rumor was it was deliberate. But most of the 8088 designs were not well cooked and werern't so reliable. Allison >Cheers, >Chuck

17 years, 3 months

8088 vs. 80c88

by les＠frii.com

1) I can attest that the V20 runs cp/m80 (2.2), wordstar, word master, asm, mac, load, ddt, collasal cave adventure, logicalc. I just verified these things yesterday. 2) Here's the one with JRT Pascal (IIRC): LXI SP,LABELX CALL LABELX LABELX: ... Does the 8080 decrement the sp before it pushes the return address, or after. If its after, that code would of course not work. I can't remember which order that happens in, although I suspect that it decrements before pushing. Another possibility (seems more likely) is that the loading of the stack pointer is not finished before the next instruction is executed. I am trying to remember which register was used for the sp in the emulation mode. (I think it may be BP????) In this case, as long as some instruction gets executed between lxi sp,xxxx and the first push/pop/call, it may not show up. In any case, this seems like a rare issue, as most programs (thats a big undefensable statement) would set the sp when they start, and then leave it alone. Related, I found a bug in Spellstar for DOS. It worked fine on an 8088 or 80286, but crashed on a 386 (it could have been a 486). Here is what the code did: 100 mov dx, address of routine to jump to 103 mov [121],dx .. .. .. .. .. 120 jmp 0000 This little piece of self modifying code worked great until the instruction queue in the cpu became large enough that the jump instruction was already in the pipeline before it was modified with the desired address. I was able to fix this with a jmp dx instruction, but compilers do generate odd code sometimes. The question becomes, did the 386 have a bug, or is this just a software issue? Les

17 years, 3 months

VAX cables for the cost of postage

by pcoghlan+cctech＠vms.eurokom.ie

> >> A weird DEC cable, DB25 male on one end, and what I think is QBus >> female on the other (3 rows of pins, 17/16/17 - DB50?). I'm guessing >> this will be a huge score to someone, just not sure what it goes >> with. :) > >I'm not sure how fair it is to call a DD50 "Qbus", since Qbus is a >card-edge connector bus. > The Qbus sockets on the back of my Vax 4000-100A are DD50 so I guess DD50 connectors are used on Qbus cables for at least some applications? > >>But this might be a SCSI cable; I've seen both DB25 and DD50 used for >>SCSI (D-shell SCSI in my experience always uses male connectors on the >>cables, but my experience with DD50 SCSI is pretty much limited to >>Suns). It might be useful to buzz it out.... >> > It sounds to me like a V.24 adapter cable for something like a DEMSA X.25 router and various other DEC synchronous serial items. This would seem to be a BC19D-02 from what I can find. Is there a part number stamped on it? See http://www.islandco.com/cables.html#bc19d Regards, Peter.

17 years, 3 months

Dumping MCM6832 PROMs

by derschjo＠mail.msu.edu

Anyone out there have the capability to dump Motorola 6832 PROMs? I'd like to dump the rom sets from my Tek 4051 (and expansion packs) for some reverse-engineering but I don't currently have any means to do it. (Can't use the Tek to do it since the system software is BASIC only and has no low-level memory access functionality.) Ultimately I'd like to be able to build a custom expansion ROM pack with my own code on it, and eventually write a 4051 emulation. (And of course if anyone out there's already dumped this stuff, I'd love to get a copy...) Thanks, Josh

17 years, 3 months

Powering up a 20-year old MicroVAX II

by RodSmallwood＠mail.ediconsulting.co.uk

They can often go down internally without the top going. Some have vents that end up next to the PCB. I did four years in a high voltage test lab. And..... Yes they do pop and they can explode! Rod Smallwood -----Original Message----- From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] On Behalf Of Gordon JC Pearce Sent: 23 February 2009 10:25 To: On-Topic and Off-Topic Posts Subject: Re: Powering up a 20-year old MicroVAX II Rod Smallwood wrote: > Hi > Sounds like capacitors. > Alhough it's a switcher any high voltage/high value capacitors in the > PSU might well need reforming. > Quite often you will see caps with a pair if incised lines on top. > This makes them go pop instead of bang. > You would not want to see a PSU where they have gone bang. This is the only popped electrolytic I have ever seen, in damn near 30 years of fiddling with electronic stuff: http://www.gjcp.net/~gordonjcp/blowncap.jpg Gordon

17 years, 3 months

Can someone help me identify this IBM machine?

by mwichary＠gmail.com

I spent 20 minutes on Google without much luck: http://www.flickr.com/photos/mwichary/3300685689/ It seems like a calculator. Thanks in advance! -- Marcin Wichary Sr. user experience designer, Google Graphical User Interface gallery >> www.guidebookgallery.org

17 years, 3 months

Electrolytics

by tshoppa＠wmata.com

>>> I have to say, for all the talk of failing caps in power supplies >>> I've only ever seen one electrolytic cap fail *ever*, and that was >>> last week in a one-year-old graphics card that has hardly ever been >>> powered off... >> >> > Gordon, you don't mention how many caps you've looked at or tested, or > how you've done so, but I encounter them constantly. Not so much in > the 1980's vintage DEC equipment YET, but it's no myth that AEC's are > electrochemical vats that have a lifespan. The lifespan varies widely > depending on many factors, heat being the big one. My gut feeling is that electrolytics got a lot lot better in the 70's compared to earlier generations. It's not just that they're 20 years newer than the ones from the 50's, they really were better quality to begin with. I work on old radios and it's pretty much a given that any set has electrolytics in need of replacement. If the set was used for a while, in fact some lytics were probably already replaced in the 50's or 60's, and maybe the replacement needs replacement today. "Failed" is a relative term... it's easy to find electrolytics leaky enough that they no longer meet their original spec, or leaky enough that they get warm. But the set still works. Other times they literally explode, or they cause other components in the circle to fail catastrophically... my experience is that switching supplies are far more sensitive to out of spec ESR's in electrolytics than any old radio ever was. Tim.

17 years, 3 months

servicing terminals/monitors

by slawmaster＠gmail.com

I've got a quick question about power safety here. My ADM-3A has needed fiddling for a while, since what I believe is the flyback is making a very high-pitched whine that gives me a splitting headache and makes it hard to see straight after 5 minutes. I want to take a poke around, make sure everything is connected firmly, make sure none of the components are visibly bad, that kind of thing. How long does it take an unplugged CRT to discharge? This hasn't been plugged in for over a month, so I figure it's probably safe right now, but if I test it and then want to check something else, how long do I need to leave it sit? Is there a safe way to discharge a CRT when you're working on it in the living room? I'm a little leery of just shorting connections with a screwdriver randomly, although that's almost exactly what I did the first time I worked with a CRT :) (it was 5th grade, and I had just had it on, unplugged it, opened it, and started poking around with wires. BIG SNAP) Thanks John -- "I've tried programming Ruby on Rails, following TechCrunch in my RSS reader, and drinking absinthe. It doesn't work. I'm going back to C, Hunter S. Thompson, and cheap whiskey." -- Ted Dziuba

17 years, 3 months

Powering up a 20-year old MicroVAX II

by js＠cimmeri.com

-----Original Message----- > From: cctalk-bounces at classiccmp.org [mailto:cctalk- > bounces at classiccmp.org] On Behalf Of Robert Jarratt > Sent: 20 February 2009 22:45 > To: cctalk at classiccmp.org > Subject: Powering up a 20-year old MicroVAX II > > I have just collected a MicroVAX II which has been in storage and has > not > been powered on for 20 years. This is my first machine of such an age, > unfortunately I am not particularly knowledgeable at the electronics > level > (I studied circuits academically 25+ years ago and can solder a bit, > but > that is as far as it goes). I know I will need to treat it carefully in > order to get it working again. I plan to open it up and make sure I > clear > out any debris etc, but beyond that I need advice from those with the > experience and knowledge that I lack on how to go about powering it up > carefully. > Thanks Rob > After removing all the boards and leaving just the disk and tape drive for load I impetuously decided to try powering it up. I knew the PSU (model H7864) was set for 110V and made the switch to 240V (I am in the UK). When I connected the power cord, after a few moments there was a loud pop, followed by another before I could pull out the power cord, smoke rose from the PSU. This sounded just like when I had once accidentally made a 110/240 mix-up. The question is, could it be that I had not made the switch to 240 correctly, or could this just be down to the age of the PSU? ---- *Rob, possibly you made the 110/240 switch wrong, but also possible is that the PSU just wasn't ready to be turned on like that. Electrolytic Capacitors (of which there are many in that PSU) tend towards non-functionality the longer they sit unused. Without those caps working right, the PSU will do pops, smokes, and other alarming things. Then good luck fixing it. What I do with an old PSU like that is test each cap prior to it ever being powered up.. both for capacitance and ESR. Usually, some or all of the caps need reforming or even replacement. Only after the caps are back to health, do I then give the PSU power... at first with the smallest load I can get away with. If it's a switcher PSU (as that one is), I'll bring it up quickly to about 90V using a variac... then in 5V increments every 1/2 hr after that to 130V, then back down to 120V. This in the USA. jS *

17 years, 3 months

TransEra documentation

by aek＠bitsavers.org

Going through my Tek 405x stuff, I realized I hadn't uploaded anything >from TransEra, who was a third party supplier of firmware. http://bitsavers.org/pdf/transEra

17 years, 3 months

Powering up a 20-year old MicroVAX II

by chd_1＠nktelco.net

Robert Jarratt wrote: > The harness in my system does not seem to match any of the descriptions I > have seen so far. The wires are not equal in length, but it is not a ribbon > cable with IDC connectors either. The connectors are black rather than > white. The harness wires do not seem discoloured, but I believe that this > particular system may have only had light use in its day. I have a picture > of the harness but I am not sure if the rules of this list allow > attachments. > The key point of your description is that the wires are not equal in length. This COULD be a bad thing. I have a BA23 chassis that had a melted power supply connector. The connectors were AMP MTA .156 IDC connectors with individual wires. The connector housings were Yellow. The failure point was the connection between the harness and the power supply pin. As Allison describes, the problem is that there was an unequal distribution of current between shared pins. I replaced the harness with one that I made myself using high current box connection pins... with equal length wires. There is a field service notice that describes the problem and even mentions the color of the connectors. I remember reading it and saying to myself that was my chassis. I just can't remember where... -chuck

17 years, 3 months

AAARRGGGHHHH ... people still stealing my work

by evan＠snarc.net

>>> Else something more wordy and crafted in legalese, rather than a plea. I hate legalese. I was trying to be nice. :)

17 years, 3 months

Advice for Tek 4051 vector-drawing issue?

by derschjo＠mail.msu.edu

Inherited a Tektronix 4051 this afternoon (really, really cool old machine - 6800 CPU, vector storage-tube display) and after cleaning it out and reseating the socketed chips it appears to work almost correctly. (Even the tape drive works after cleaning the head... amazed that the pinch roller hasn't turned to goo.) The one issue is that "long" vectors do not get drawn as straight lines -- they end up curving in the direction of the destination. I've taken a photo to demonstrate: http://yahozna.dyndns.org/computers/tek4051/unvector.jpg The above is _supposed_ to be drawing a line from 0,0 to 100,100 and back, but as you can see, it's not really doing a very good job. Short vectors seem to draw OK, as do perfectly vertical and horizontal ones. Text gets drawn fine. I have the schematics but I've never dealt with a vector-based display before (only other vector display I have is in my Vectrex, and I haven't had to tweak that one yet.) Any ideas where to start? I figure the D/A converters on the CPU board are working correctly since text positioning works, and the endpoints of the vectors seem to be correct. Bitsavers has the schematics at: http://www.bitsavers.org/pdf/tektronix/405x/070-2286-00_4051_Service_Vol2_M…, (see page 92 for the start of the display schematics.) And a higher-level overview of the functionality at: http://www.bitsavers.org/pdf/tektronix/405x/070-2065-00_4051_Service_Vol1_M… (See page 147 for the start of the display overview.) Thanks! Josh

17 years, 3 months

Powering up a 20-year old MicroVAX II

by ard＠p850ug1.demon.co.uk

> > > *Rob, possibly you made the 110/240 switch wrong, but also possible is > > that the PSU just wasn't ready to be turned on like that. > > Electrolytic > > Capacitors (of which there are many in that PSU) tend towards > > non-functionality the longer they sit unused. Without those caps > > working right, the PSU will do pops, smokes, and other alarming things. > > Then good luck fixing it. > > Do you mean that it will be difficult to fix, even if I can find someone who > really knows what they are doing? It might be. It depends on just what's failed. In SMPSUs (Switch Mode Power SUpply Units), one component failure can wreck other components too (ecven to the extent of multing PCB tracks) and if you don't find _all_ the failed partsm, but juet replace some of them and turn it on again the same thing can happen again. > > > > > What I do with an old PSU like that is test each cap prior to it ever > > being powered up.. both for capacitance and ESR. Usually, some or all > > of the caps need reforming or even replacement. Only after the caps > > are back to health, do I then give the PSU power... at first with the > > smallest load I can get away with. > > I only have a basic multimeter so I don't know if I would have had the > necessary equipment to do this, do you have any advice on the minimum > equipment needed? Now that there has been some damage is it sensible to You need a multimeter, certainly. An ESR meter is very useful too (this measured the effective series resistance of a capacitor, basically the higher the value the worse the capacitor is). A good 'scope is handy, and if you want to owrk on the primary side of the PSU when it's running, or examine waveforms there, you need a mains isolating transformer. And the 'series light ulb' (a mains-rated lightbulf, or 2 in series, conencted in series with the DC supply to the chopper circuit to limit the current in the event of a catastrophic failure) will save your nerves and possibly some expensive components [1]. But very important is a _brain_ :-) [1] THe fact that mains-rated light bulbs are getting hard to get thanks to the governemnt does not help here! > replace the blown capacitors and any other ones that don't measure well? > > > > > If it's a switcher PSU (as that one is), I'll bring it up quickly to > > about 90V using a variac... then in 5V increments every 1/2 hr after > > that to 130V, then back down to 120V. This in the USA. > > I looked up variacs but there seem to be an awful lot of different ones, > again any recommendation as to the minimum I would need? I would recomend against using a Variac on an SMPSU unless yoy really know what tyou are doing. An SMPSU is a fairly good aproximation to a contant _power_ load, in other word the input current increases as the input voltage decreases. Some SMPSUs can actually be damaged by running them at too low an input voltage, while plenty of other types do strange things. > By the way, I am aware that PSUs can be very dangerous to meddle with when > you have limited knowledge. How long should I leave the PSU between any Indeed. Mains, and the rectified mains you find in SMPSUs, is probably the most danagerous voltage you're going to come across. > tests to allow the capacitors to discharge? The label on the PSU says to > leave it 5 minutes, I suspect it should be longer. It's impossible to say. A good electrolytic capacitor with nothing connected to it will hold the charge for quite a time. Of course when the supply is working, the chopper circuit tends to discharge the mains smoothing capacitors, so the charge won't remain for very long. And many supplies have bleeder resistors (resistors connected in parallel with the mains smoothing capacitors) to discharge them. But of course those could fail too. What I do is open up the supply carefully and then measure the voltage across the mains smoothing capacitors (sometiems, as in the case of the HP9845 and DEC PDP11/44 supplies there are clear testpoints to do this). If it's more htan a few volts, I carefully connect a suitable resistor (a few 10's of kilohms) across the capacitors to discharge them. -tony

17 years, 3 months

Advice for Tek 4051 vector-drawing issue?

by aek＠bitsavers.org

> I'm looking into whether if it's possible to adapt one of the "backpack" > expansions to take EPROMs instead of MCM6832 ROMs. Later modules used EPROMs. I've put everything I had dumped up under http://bitsavers.org/bits/Tektronix/405x along with scans of the binary loader and real time clock pcbs.

17 years, 3 months

GPIB cards [WAS: Re: Advice for Tek 4051 vector-drawing issue?]

by devonstopps＠gmail.com

Speaking of GPIB cards, if anyone needs an ISA GPIB interface card, let me know. They're usually NI AT-GPIB/TNT+ cards. We usually toss a few every couple of months. For the cost of shipping (about $15CAD to almost anywhere). Also have Sun Ultra10 and Ultra5 free for pickup in Kingston, ON. On Sun, 22 Feb 2009, Josh Dersch wrote: > > Richard wrote: >> >> I guess the best way to get data transferred from these systems is to >> >> use the GPIB interface and transfer the programs out of the system and >> >> into the internet. I wonder if the easiest would be to use a >> >> Commodore GPIB compatable floppy drive or something.

17 years, 3 months

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