test-drb September 2002

test-drb@ccmp.vtda.org

217 participants
408 discussions

by Antonio.Carlini＠riverstonenet.com

>2) What are the differences between the 4000VLC and the 4000-500? Are there >likely to be some serious gotchas in there? The VLC (as you know) is small, uses one low profile SCSI disk internally, has an external SCSI connector, supports a max of 24MB or memory and weighs in at 6 VUPs or so. There is no real expansion available. A VAX 4000-500 is bigger (coffee table size), usually comes with DSSI drives (although it can use SCSI with the right additional h/w) can have many disks, supports more memory (512MB max - 32MB min!) and runs at 24VUPs on a bad day (more if it is really a -700A or 705A). DSSI is available for storage and the box has a Q-bus. Whether any of this matters or not depends on what the VAX is supposed to do. If they wanted an OpenVMS compute engine, almost any cheap Alpha would eat both of the above for breakfast, so I assume that there is either a software constraint (e.g. VAX-only 3rd party s/w) or a hardware one (must use this Q-bus interface card). Antonio

22 years, 2 months

Brian Instruments BRIKON Mdl 723 Floppy Drive Tester / Analyzer

by rigdonj＠cfl.rr.com

Does anyone here have access to one the model 723 floppy drive testers with the analog/alignment attachment (option R)? If so can you send me the pin out of the I/O cable for analog attachment? I think there's only six or eight leads on it? Joe

22 years, 2 months

Altair-what do I do first

by dwightk.elvey＠amd.com

>From: "Peter C. Wallace" <pcw(a)mesanet.com> > >On Wed, 25 Sep 2002, Patrick Rigney wrote: > >> > Better still, if you are testing the cards one at a time with an external >> > supply, tack on a 5V (set to 5.5 or so) crowbar on the output side of the >> > local 5V regulator -- no cut traces, only tacking on 2 wires >> > temporarily... >> > >> > Peter Wallace >> >> Peter, yeah, this seems like an easy approach. Question: could a simple >> 6.2V Zener be installed reverse-biased from the 5V regulator output to >> ground? Seems like you'd want inline fuses between the unregulated supply >> and the backplace as well for this kind of test... >> >> Patrick >> >> > > You would have to have a monster zener to be safe, probably 50 W or >so. Those arent that common. A crowbar circuit stolen from another supply or a >home made one would be better than a zener. > > Instead of a crowbar (that usually use SCRs), You could also use a >5.6v or so shunt regulator made with a big (20A) power transistor and a 5V >10W zener... > >Peter Wallace > > Hi I think you are all a little paranoid. Regulators rarely fail in storage. If it is blown, it most likely blew while the power was on and any damage has already long since been done. That being said, there is a failure that can happen in storage that is related to the regulation. Many regulators, especially the TO-3 types need the screw holding them to the board to have a vary good connection. If this is bad, the voltage will go unregulated and it will over voltage. You should remove and check under these screws to look for corrosion and clean the surfaces. I recommend a star washer between the PCB and nut/washer. This should be checked on any electronics that has been stored. Often this is a good point to restore some fresh heatsink compound as well. The old dry stuff is less effective. The most common failure is the old electrolytics and the tantalums. I've seen flames from a blown tantalum. If you connect a voltmeter to the output leads of any regulators and watch the voltage as you bring the line up with a variac ( adjustable auto-transformer ), you should be able to catch any over voltage before it does any harm. ( note: don't use a variac on a switcher supply! ) Later Dwight

22 years, 2 months

VAX 4000-500 near Texas?

by dittman＠dittman.net

> Dunno whether this is on-topic or not, apologies if not. Someone at > my institute needs access to a VAX 4000-500 or similar series machine for a > proposal for some project work. I intend to loan my Vax 4000 VLC to them, > but: > > 1) Does anyone near San Antonio Texs, have a qualifying machine that they'd > like to unload permanently, hopefully at a reasonably good price? I have a VAX 4000-500 I'm looking to sell, but I'm in Plano, Texas (northern suburb of Dallas). -- Eric Dittman dittman(a)dittman.net Check out the DEC Enthusiasts Club at http://www.dittman.net/

22 years, 2 months

RSTS/E Manuals???

by xds_sigma7＠hotmail.com

Hi, I recently accquired a really, really random assortment of RSTS manuals, >from V06B up to like V9.6 or so, and I'm attempting to make sense of what portions of docsets I have parts of.. If anyone has extra manuals, that'd rock, but I also could really use copies/scans/etc. of the documentation directories, since the only one I have is for V7.1 haha Will J _________________________________________________________________ MSN Photos is the easiest way to share and print your photos: http://photos.msn.com/support/worldwide.aspx

22 years, 2 months

Keyboard adapter for ??

by lgwalker＠mts.net

I picked up an ordinary Fujitso KB at a thrift shop that had an adapter on the end of the cable. It's a small plug and the only markings on it were the common I/O arrows on the business end. One side is the regular F 5-pin Din but the male side is about halfway between a regular din and a PS/2 sub. It is in a 6-pin configuration but the pins are much thinner than usual. It only has 4 pins which would square with the 5v, grnd, clock, data requirements but it could have a pin(s) broken off since they're fragile and protrude from the shell about 3/8". Clockwise the 1 and 3 are missing. There's no center lock. Anyone have any idea of what this might be for ? Lawrence lgwalker(a)mts.net bigwalk_ca(a)yahoo.com

22 years, 2 months

CPM-8000 running

by dwightk.elvey＠amd.com

Hi Chris Groessler and I have been working with the CPM-8000 images that we found on the unofficial CPM page, along with manuals and such found elsewhere. Last night, I was able to get the CPM-8000 prompt and execute both commands that I tried ( DIR and USER ). There are still some minor issues but things should be moving right along ( why can't programmers realize that initializing variables is an important part of any program? ). I want to give thanks to Hans, without the hardware manual he scanned, I wouldn't have been able to figure out the address decoder PROM in my Olivetti M20 and find out how to bring my machine up to 256K of RAM ( needed by CPM-8000 ). We still have some work to do ( building up the disk with all of the files ) but it looks like a down hill trip from here. Later Dwight

22 years, 2 months

Altair-what do I do first

by kapteynr＠cboe.com

All good advice so far -- but one caution I forgot. My experience is that the CMOS chips from this period are THE MOST STATIC SENSITIVE chips that there are. It is much easier to damage these whith inappropriate handling than any modern stuff. Use paranoid static handling precautions. Since I usually work on these machines on those cold (dry) winter days when static forms easily, I also use a humidifier in the room where I work. -Rob -----Original Message----- From: cctalk-admin(a)classiccmp.org [mailto:cctalk-admin@classiccmp.org]On Behalf Of J.C. Wren Sent: Tuesday, September 24, 2002 8:08 PM To: cctalk(a)classiccmp.org Subject: RE: Altair-what do I do first A less painful way may be to lift the output pin of the regulator >from its via. Or (and this is evil, but works, and is can be better than losing all your unsocketted chips), cut the trace after output of the regulator. You can always use a piece of foil tape or wire to effect a repair. This may detract from the ultimate value of the board, but you're far less likely to wreck it than removing irreplacable socketted chips. --John -----Original Message----- From: cctalk-admin(a)classiccmp.org [mailto:cctalk-admin@classiccmp.org]On Behalf Of Tony Duell Sent: Tuesday, September 24, 2002 20:24 To: cctalk(a)classiccmp.org Subject: Re: Altair-what do I do first > > Good move -- don't plug it in yet. _Neve_ plug in a classic computer without checking it first! [Good advice on electrolytic caps deleted] > In any case, detach everything from the power supply and check it out first. > Unfortunately, Altairs have no connectors for this, so you will have to > desolder the wires. > Some suggest powering it up slowly on a variable transformer, but I have not > tried that. > > After checking out the power supply voltages, unplug all of the cards and The amin problem with S100 systems is that the PSU lines on the bus are unregulated. The voltage regulators are on each card. And this means that a defective regulator _on a card_ will wipe out all the chips on that card, and may even put high voltages onto the bus lines and damage other cards. Therefore, do as suggested and get the unregulated PSU working first. Then take the cards (one at a time) and remove all socketed ICs. Make a diagram first, of course if you don't have the schematics/layout diagrams for that card. You'd better hope that the expensive/rare ICs (CPU, ROMs, RAM, LSI I/O chips) are socketed. Then put the (essentially bare) card in the backplane and check the outputs of the regulators on that card. Repeat for all the cards you have. Put the ICs back into a card before starting on the next one (unless you are a lot better organised than me!) Then, and only then do you put populated cards into the backplane and start testing logic functions. -tony

22 years, 2 months

VAX 4000-500 near Texas?

by mtapley＠swri.edu

All, Dunno whether this is on-topic or not, apologies if not. Someone at my institute needs access to a VAX 4000-500 or similar series machine for a proposal for some project work. I intend to loan my Vax 4000 VLC to them, but: 1) Does anyone near San Antonio Texs, have a qualifying machine that they'd like to unload permanently, hopefully at a reasonably good price? 2) What are the differences between the 4000VLC and the 4000-500? Are there likely to be some serious gotchas in there? - Mark

22 years, 2 months

DEC PDP-11/73 in GA

by xds_sigma7＠hotmail.com

LOL! Well, my parents apparently are willing to agree there's nothing called too many computers, so long as they are put away nicely, not filling the garage, spread through the house, etc.. Heh.. Will J _________________________________________________________________ Chat with friends online, try MSN Messenger: http://messenger.msn.com

22 years, 2 months

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test-drb September 2002