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101090 discussions

DEC VR260 service docs / common failure modes?

by derschjo＠gmail.com

Hi all -- Picked up a non-functional but otherwise nice looking DEC VR260 (19" b&w monitor) on the cheap, hoping to use it with my VAXstation 2000. From what I've read, these were never the most reliable displays. Curious if anyone has any information on common failure modes, or has service docs squirreled away somewhere. I've at least found schematics, so I have something to go on, but it's not exactly the most straightforward design I've poked at. Right now when powered up I hear a repeated low hum from the transformer followed by a soft ticking noise so I'm guessing I've got power supply issues at the very least. Unsure what I should expect the monitor to do if it's not being fed a valid video signal (I haven't yet tried to hook the VS2000 up to it) -- whether it'll go into free-running mode or do mostly nothing until it has something to sync to... Thanks as always, Josh

5 years, 8 months

Acer-Altos System 4500

by marco＠familie-rauhut.eu

Hi List I have here a Acer-Altos System 4500. It is a 486/33 EISA System with an Altos Basic SCSI Bsc(e) Controller. It has an Altos Multidrop/2 EISA Controller (to controll TCU Boxes that handle RS232 Ports) and a VGA1024i EISA Graphics controller. My mision is to bring that System back to life respectively get access to the Discs. The built in SCSI Disk are running and i have created Images of this Disks in a Linux PC. But i can not boot the System by one of this Disks. I remember that on this disk is some sort of Altos SCO Unix System V installed. Did sombody here on the list have documentation or the original Installationmedia (QIC-525) for that system? Marco

5 years, 8 months

Burroughs L-series paper tapes

by sieler＠allegro.com

> > Mike Stein writes: > > I remember there was another L9000 rescued in California years ago, > but maybe that's the one you have now. > My consulting company was in Redwood City, CA. Our nextdoor neighbor had a company leasing new cars. They ran the company on a Burroughs L9000. About August of 2000, they were at the point where they could no longer obtain ledger cards (roughly 8x11 with a magnetic stripe down the side for computer data), for the L9000, so they were going to move to a PC-based system. The owner knew I was a computer collector, so he offered to give me the L9000. I was tempted...but it was a large machine, so I arranged for it to be given to the Computer History Museum (where I was, or became (timeline hazy) a senior docent). I remember the owner saying that only the cleverness of their independent maintenance guy had kept the machine running ... to the point where he'd machined some replacement parts himself. I talked to the elderly lady who ran the machine (i.e., did the data entry). She compared it to the PC, and lamented the loss of the L9000. The L9000 was so much faster and easier to use! She could probably enter data four or five times faster on the L9000. It wasn't just a matter of familiarity ... much of the slowdown was due to the GUI nature of the PC program they switched to, and they no longer had the luxury of having relatively purpose-related hardware on the L9000. Stan

5 years, 9 months

RSTS Professional scans

by aek＠bitsavers.org

almost finished with this http://bitsavers.org/pdf/dec/magazines/RSTS_Professional I'd like to gap-fill the rare RSTS Professional issues if anyone still has them. They are staple-bound so they can be scanned without removing a binding.

5 years, 9 months

Burroughs L-series paper tapes

by michael.99.thompson＠gmail.com

There is a B800 at the RICM, but nothing larger. > On Aug 5, 2020, at 1:00 PM, cctech-request at classiccmp.org wrote: > > Burroughs L-series paper tapes

5 years, 9 months

Burroughs L-series paper tapes

by Flash688＠flying-disk.com

Al Kossow <aek at bitsavers.org> wrote: > On 8/3/20 7:25 PM, Mike Stein via cctalk wrote: > >> And what about your L9000 (or was it an 8000?) ? Did it also go to the LCM? >> >> Not many left, alas... > > we have an L-9000 > https://www.computerhistory.org/collections/catalog/X1742.2001 Here is another one: In 2006, Nelson Nameplate Company (now Nelson-Miller) gave their L9000 to Sellam Ismail at Vintagetech.com. He already had an L7000 and was anxious to add the L9000 to his collection. Nelson had wanted to donate it to a 501(c)(3) institution, but nobody was interested. They bought it in 1975, and it was in daily use in their billing department until November 2005. They certainly got their money's worth out of it! Amusing side note: The repair guy who kept it running for many years had the unfortunate name of Slobodan Milosevic. He preferred to go by simply "Dan". :-) Alan Frisbie

5 years, 9 months

Burroughs L-series paper tapes

by aek＠bitsavers.org

I've bought a small number of L-series tapes over the years that I finally read yesterday, mostly pass 1 and 2 of the assembler. Part numbers look like this. Oddly, they all seem to be wound backwards. The person-readable label is at the end, which will make it annoying to scan. 1-2101-049-01 1-2101-052-07 1-1001-008-07 1-1001-009-07 Anyone have any others?

5 years, 9 months

HP 1000 Series A400, A600, A700, A900, A990 RTE Systems - Maintenance companies

by jesse＠cypress-tech.com

Are there any companies or entities left out there that are still doing hardware support on the older HP A900 / A990 systems? Looking for Worldwide people or companies. I get requests form time to time and don't know where to send them. Thanks Jesse Cypress Technology Inc jesse(at)cypress-tech.com

5 years, 9 months

A tale of two Automated Logic Diagram Sheets

by cube1＠charter.net

I encountered my second missing Automated Logic Diagram (ALD) page for the IBM 1410: 13.64.03.1, which, based on the signals fed to it and which it produces, would, fortunately, necessarily have the same logic as page 15.41.10.1 - "E CH FULL CONTROL-ACC". Page 13.64.03.1 is for the second, or F Channel. The E Channel version uses 9 NAND gates and 4 drivers. However, based on the card location chart, the F Channel version, even though it would have corresponding logic, has TWENTY-ONE gates (some of those could be just load resistors) on card type DGR. These are ALL just INVERTERS. The card location chart also calls out 2 gates on card type DFS - also inverters, and one gate on card type AEK which uses equation (NOT IN1) OR IN2 to produce its output. The F channel logic used up two cards slots plus parts of six others. The E Channel logic version used three card slots (probably in their entirety) and the drivers used parts of four other cards slots What to do? As readers will likely know, you can't do any real logic with just inverters. However, SMS card outputs can be hooked together with all but one of the gates so connected (or "DOT-ed") having open collector outputs. Electrically, given the circuits on the DGR and DFS cards (as well as most others the IBM 1410 uses), if you follow that with an inverter you get OR => NOT, aka "NOR" logic. Now that we can do something with. So, I wrote a VHDL test bench, based on the Intermediate Logic Diagram (ILD) that shows the necessary logic for the E Channel (and indicates the F Channel is the same), and tested that against the E Channel page to make sure my understanding of the logic was correct. Then, as an exercise, with liberal application of DeMorgan's theorems, I proceeded to lay out the logic for the F channel version in that fashion. It took 21 inverters (using the AEK as an inverter) and 1 load resistor (which I probably didn't need to use) and eight DOT functions (ORs) to produce the necessary logic. So, pretty close, but not a perfect reproduction. One thing is an issue for sure: I "DOT-ed" two inputs together that come from other sheets whose outputs are used on still other sheets - which is generally a no-no. It would not have been that way on the original machine - they would need to be isolated by being fed into gates of some sort - even if only back to back inverters. I could probably spend a bit more time, find a way to leverage the second input on the gate AEK, and get it more exact, but frankly, it isn't worth the effort right now. JRJ ?

5 years, 9 months

[GreenKeys] Omaha craigslist - Teletype RO printer - what model?

by jfoust＠threedee.com

At 12:56 PM 8/3/2020, Nick England wrote: >Looks interesting - I know nothing more ><https://omaha.craigslist.org/sys/d/omaha-heathkit-h19-terminal-vintage-old/…>https://omaha.craigslist.org/sys/d/omaha-heathkit-h19-terminal-vintage-old/… > >What model printer is that? typewheel, not dot matrix. Any ideas over here? - John

5 years, 9 months

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