test-drb January 2002

test-drb@ccmp.vtda.org

303 participants
1201 discussions

by doc＠mdrconsult.com

Anybody know anything about a Tallgrass Technologies TG-1140 Tape Storage System? Apparently takes 40MB cartridge tapes. The guy who has it thinks it was built about 1988. I don't have access to it, so that's all the info I have. Yeah, I know. Tony Duell has all the manuals.... :^) Doc

22 years, 11 months

Prophylactic replacement of electrolytic capacitors?

by pete＠dunnington.u-net.com

On Jan 14, 9:39, Gary Hildebrand wrote: > IMHO, it depends mostly on who made the electrolytics. I have large > "computer grade" electrolytics from the 60's, salvaged from Ampex VTR's > that are still 100%, and have never failed in over 30 years. Not unusual... > OTOH, the cheap electrolytics found in consumer grade electronics seem > to dry out and fail on a yeary or biannual basis. One of the worst > failure rates I've seen is the teeny tiny 160VDC electrolytics; I just > replace then no matter what and usually that cures the problems. ...and also not unusual. I've seen a batch of Pentium motherboards that had a stack of small cheap electrolytics right beside/under the Slot1 processor -- and all dried out and failed within a few months. > The best way to check those #$%#$%^# caps is to use an ESR meter. And > only then should yo buckshot them. And replace them with good grade > Spraggue or CDE if possible. I've had mixed to poor resutls with > Nichion, or other cheap Japanese caps sold by MCM Electronics. > > Gary Hildebrand > -- Pete Peter Turnbull Network Manager University of York

22 years, 11 months

Compaq LTE 5000 series, slightly OT (was: Re: Xircom NICs (wa s RE: OT: DELL SUCKS! Re: .... ))

by DAW＠yalepress3.unipress.yale.edu

! > While not quite yet a classic, one of my more favorite ! > series of laptops is the Compaq LTE 5000. It supported ! > a total of 4 pcmcia cards when it was used with a ! > docking station. These were truly unique machines IMHO, ! > and set the standards for removable cdrom and floppy ! > drives in future laptop systems. I don't know of any ! > other manufacturer at the time who offered a ! > machine with similar features. Sounds like my DockStation II for IBM Think Pads. That sucker was big, and at least half made of metal. It added 2 more PCMCIA slots, 2 ISA (or PCI) slots, included a special SCSI CD-ROM (Kodak Pkoto-CD compatible!), a full size SCSI expansion bay, an high density 50-pin SCSI connector on the back, stereo speakers, PS/2 mouse & KB connectors, printer, serial, video, audio in/out, external floppy connector... Works great with my 760EL... --- David A Woyciesjes --- C & IS Support Specialist --- Yale University Press --- mailto:david.woyciesjes@yale.edu --- (203) 432-0953 --- ICQ # - 905818

22 years, 11 months

Free VAX 11/750 (Dallas)

by mrbill＠mrbill.net

Free 11/750 for pickup near Dallas. Please contact Alan directly if interested. Bill ----- Forwarded message from Alan Andrews <alan(a)tieless.com> ----- Subject: Re: VAX 11/750 From: Alan Andrews <alan(a)tieless.com> To: Bill Bradford <mrbill(a)mrbill.net> Date: 13 Jan 2002 13:59:55 -0600 On Sun, Jan 13, 2002 at 06:25:48AM -0600, Alan Andrews wrote: > > I know it's not a PDP 11, but I have a VAX 11/750 that's looking for a > > good home. If you know anyone interested, please pass on my email > > address. I'm in Frisco, about 20 minutes north of downtown Dallas. The 11/750 has System Industries hard drives (2 450meg and 1 350meg), disk pack, tape drive, and a DEC remote diagnostic card. I got it from the company that used it for their accounting system before switching to a client/server system in the early 90's. It's been stored in my garage for about five years. I know some of it's history, and it's in good shape, although it hasn't been turned on in ten years. It's free to a good home. ----- End forwarded message ----- -- Bill Bradford mrbill(a)mrbill.net Austin, TX

22 years, 11 months

The STC ZEBRA and CPU meters

by dpeschel＠eskimo.com

Thread crossing alert... Since the ZEBRA used a drum for storage, most instructions had to wait for the drum to rotate into position, so one instruction takes a variable amount of time. And so the computer had a moving-needle efficiency meter on the front panel, which presumably integrated a series of pulses (similar to the circuit Tony described earlier). Or I suppose it could have divided the rate of instruction execution by the rate of drum rotation (since there was a timing track on the drum anyway). 100% efficiency was attainable but only by simple programs such as a parity check of the drum. It also had a telephone dial, sense switches, the usual memory-tweaking switches, and a register display. In the second-generation (transistor) machine, the register display was a CRT. In the first-generation (tube) machine the register display was a bunch of Magic Eye units IIRC. -- Derek

22 years, 11 months

Prophylactic replacement of electrolytic capacitors?

by pete＠dunnington.u-net.com

On Jan 13, 21:27, Louis Schulman wrote: > Old computer power supplies generally have big old electrolytic capacitors. When these go bad, they can > cause real problems, and damage other components. > > The literature indicates that many of these only have a working life of 2000 hrs., or a shelf life of ten years. > Obviously, this will be exceeded in old computers. I think you may have lost a digit off the working life, Louis, at least if you're referring to the sort of electrolytics found in PSUs :-) > So, should these be replaced if they exceed a certain age? If it ain't broke, don't fix it. As always, there's an exception to prove the rule. If one of a pair goes, it may be worth replacing both to get the values to match. Or in some PSUs, if one or more fails, they may all have got too hot or dried out, and at least for small ones (relatively inexpensive), I tend to replace the lot. In any case, check the others, they may be on their way to join it. The working life is an estimate based on mean time between failures (MTBF). All this says is that for a large sample, it is statistically likely that a certain proprtion will fail in a certain time. Variation can be enormous. > For the screw terminal type, is it necessary to > use "computer grade" capacitors, which can be fairly expensive? Depends. The more expensive ones may differ in a few ways: -- lower ESR and/or higher ripple current tolerance. This means they won't waste so much energy (and heat up) if used in a PSU delivering a high current. -- higher temperature rating. PSUs often get rather warm, and the higher temperature rating makes them less prone to drying out. -- longer working life (related to temperature and other factors). If one can't find the right value in the right > size package, how much extra capacitance is acceptable? Electrolytics often have a wide manufacturing tolerance. -20%+50% is still not unusual. If it's just a filter capacitor I'd say up to 2x is acceptable. The real issue is likely to be cost. Also bear in mind that a capacitor of the same size but a higher capacitance may have other differences, like ripple current rating. I recently replaced a pair of 7700mfd caps in a DEC PSU; I could only get 10000mfd in the right size. In capacitor terms, that's close enough to be considered a match. > And any higher working voltage rating is OK? Yes. -- Pete Peter Turnbull Network Manager University of York

22 years, 11 months

Atari games in limestone cavern

by Adrian.Graham＠corporatemicrosystems.com

Thanks folks :) > -----Original Message----- > From: Michael Nadeau [mailto:menadeau@mediaone.net] > Sent: 11 January 2002 23:54 > To: classiccmp(a)classiccmp.org > Subject: Re: Atari games in limestone cavern > > > It's O'Shea Ltd. at www.oshealtd.com. > > --Mike > > Michael Nadeau > Editor/Publisher > Classic Tech, the Vintage Computing Resource > www.classictechpub.com > 603-893-2379 > ----- Original Message ----- > From: "Adrian Graham" <witchy(a)binarydinosaurs.co.uk> > To: <classiccmp(a)classiccmp.org> > Sent: Friday, January 11, 2002 6:45 PM > Subject: Atari games in limestone cavern > > > > Odd subject I know, but sometime last year there was a > story of a guy in > > California (ish) who had 2 million Atari 2600/7800 games in a cavern > > somewhere and he was selling them for $2 a pop..... > > > > Anyone got a link to him? > > > > also, anyone got a spare boxed Magnavox Oddysey they'd like > to pass on > > to a UK computer museum? :) I'm talking money > here....though donations > > are always welcome! > > > > -- > > witchy/adrian > > www.binarydinosaurs.co.uk - the online computer museum > > www.snakebiteandblack.co.uk - monthly gothic shenanigans > > Linux Powered! > > > > >

22 years, 11 months

AIM65 RAM - Help?

by mhstein＠canada.com

Does anybody have a schematic or at least the DIP switch settings for a late model AIM65 with the two 28-pin RAM/EPROM sockets (not 8 x 2114)? Help would be greatly appreciated; thanks. mike

22 years, 11 months

Mac IIci

by Huw.Davies＠kerberos.davies.net.au

At 01:24 AM 14/01/2002 -0500, Boatman on the River of Suck wrote: >But A/UX sucks humongous hairy sweaty donkey balls. Them's fighting words :-) My first Unix workstation was a Mac IIcx running A/UX version 1.something. Given what Apple was trying to achieve this wasn't a bad first effort. Version 2 was more than usable, if you wanted you could hide most of Unix behind a Mac interface (sounds a lot like OS X to me :-). I never upgraded to A/UX version 3 (by this stage I'd moved the Mac home and had upgraded to a Personal DECstation). In all the years of hacking with the Mac I don't recall ever crashing A/UX and after a while there were lots of standard Unix applications ported across. I must admit I stopped using the finder and just started X11 but that was a personal preference. Huw Davies | e-mail: Huw.Davies(a)kerberos.davies.net.au | "If God had wanted soccer played in the | air, the sky would be painted green"

22 years, 11 months

Mac IIci

by mythtech＠Mac.com

>Can I use my 9 pin parity simms from my old 386? The parity bits are >just ignored right? If so, then I can drop 32megs into it. I just scanned apple's TIL, and it looks as though Parity chips are ok on the IIci. I base this off an article discussing the fact that it needs FPM memory 80ns or faster (the article indicates that pretty much all 30 pin chips 80ns or faster will be FPM). It lists a few part numbers for ram upgrades offered by apple... two of them are Parity chip packages. So if apple is telling you that those are available as upgrades for the IIci, I have to assume parity memory will be just fine. And the IIci will handle a max of 128mb (8 - 16mb chips). You must install RAM in groups of 4 however (and I am fairly sure all ram in a grouped bank must be the same type, so either all parity, or all non parity) -chris <http://www.mythtech.net>

22 years, 11 months

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test-drb January 2002