test-drb

test-drb@ccmp.vtda.org

101090 discussions

by jnc＠mercury.lcs.mit.edu

> From: Chuck Guzis > BTW, what do you use to read UNIX v7 tar files? Linux/BSD modern tar > seem not to like the old archive format I have a very slightly hacked version of the V7 tar, which runs under Windows (under Cygwin). It read all the older TAR files which the newer TARs barfed on. Is that of any use to you? Noel

10 years, 10 months

Unusual stuff inside computers

by rickb＠bensene.com

A faded semi-nude 4x6 photo of a woman on a beach inside an IBM PC-XT that I found in a thrift shop many years ago. How or why it was in there is anyone's guess. -Rick

10 years, 10 months

Unusual stuff inside computers

by vlad.stamate＠gmail.com

Hi, I recently got a very nice HP 9816 with a 9121 drive unit from Earl Baugh (thanks Earl!). The computer worked fine but the primary drive of the 9121 refused to read the disk and made a continuous beating noise. After I cleaned it on the outside I opened it to see what is wrong with it. And I found this piece inside the drive itself: http://imgur.com/dlqOexX (floppy added for size comparison). After carefully removing it, the drive actually worked like a charm and I was able to boot from it. I was pleasantly impressed that the drive head has not been damaged bumping in the leather piece all the time. I am not sure how that got there, I assume a child pushed it in by mistake? I am not sure what it is either, the leather triangles sewn together by hand it seem. What other strange pieces did you find when you opened up classic computers? Vlad.

10 years, 10 months

SPARCClassic won't boot cdrom

by michael.99.thompson＠gmail.com

> From: Benjamin Huntsman <BHuntsman at mail2.cu-portland.edu> > Subject: SPARCClassic won't boot cdrom > > Hi all! > I recently acquired a SPARCclassic, which is my first bit of Sun > hardware. Having an awful time getting it to boot from the CD-ROM. I have > tried a bunch of different terminators and several different cables, but > whenever I try to boot I get this: > > ok boot cdrom -s > Boot device: /iommu/sbus/espdma at 4,8400000/esp at 4,8800000/sd at 6,0:d File > and args: -s > The SCSI bus is hung. Perhaps an external device is turned off. > > Any ideas as to what might be wrong here? The thing does not seem to > send any commands to the CD-ROM, as the LED never comes on and I don't hear > it doing anything... > > Thanks! > > -Ben > The terminator on the end of the SCSI bus needs to be powered. Without power on the terminator the bus will hang. Sometimes the power comes from the SPARC through the SCSI cable, but not all SCSI cables pass the power. Sometimes there is a jumper or switch on the last drive to enable SCSI terminator power. -- Michael Thompson

10 years, 10 months

This Hobby Is Actually Useful!

by robert.jarratt＠ntlworld.com

Today I was able to repair the LCD monitor (admittedly a cheap one) on my son's computer by replacing some of the electrolytic capacitors. Had I not got into collecting and restoring (sometimes) old DEC machines, I would not have had the ESR meter, the de-soldering and soldering equipment, suitable capacitors and sufficient knowledge (generously provided by many on this list) to do the job. Of course, compared to the things that many people on this list do, it is hardly a major achievement. But this hobby has now saved me from throwing away an old monitor and having to buy a new one. I suppose I now have at least some justification in the eyes of She Who Must Be Obeyed for continuing with this hobby J Regards Rob PS A related question. I struggled somewhat with the Weller Magnastat No. 8 tip, when trying to solder leads to the ground plane, I could not get the solder to stay molten very long. I was using lead-free solder, its melting point is much lower than the temperature which a No. 8 tip reaches. The iron is 50W. Clearly the ground plane was taking heat away, but is it a problem with the tip not being hot enough, the iron not powerful enough, or perhaps some operator error?

10 years, 10 months

paging mouse (rodents/montreal)

by jwest＠classiccmp.org

Sorry for the public post, can't get through privately. But oddly, the list seems to make it through. Very strange. Mouse, tried sending you a few replies, but your mail server sends rejections back from your MX host. Any chance you could whitelist the classiccmp.org server IP? Best, J

10 years, 10 months

Printer manuals that must go!

by auringer＠tds.net

Good morning all! I have the following printer manuals that I must get out of my space. If you want any of them enough to make it worth my while to ship them, let me know soon. They will be out of here by next Monday, one way or another. Shipping from Madison, WI 53714. Comrex ComRiterIIE User's Guide Gemini-10X/15X Users Manual Citizen MSP-40/45 User's Manual Wespergroup Model DLP-1132 Printer Controller User's Manual digital Letterwriter 100 Operator Guide Dataproducts Model 9030/9040 Printers Operating Guide Fujitsu M304X Series Line Printer Operator's Guide HP 7580B, 7585B, and 7586B Drafting Plotters Interfacing and Programming Manual HP 7580B, 7585B, and 7586B Drafting Plotters Interfacing and Operator's Manual Mannesmann Tally Spirit-80 Computer Printer Operator's manual Star Micronics radix-10 PC radix-15 PC User's Manual Panasonic KX-P3151 Daisy Wheel Printer Operating Instructions -Jon

10 years, 10 months

PDP-12 at the RICM (Michael Thompson)

by michael.99.thompson＠gmail.com

With a lot of help from Dave Gesswein and Warren Stearns we were able to get the MARK12 PDP-12 tape formatting program off a LINCtape and int paper tape format. Running it showed that a diode on the field-0 core stack had failed during the week making memory in the range of 4000-5000 unusable. Fortunately we had a spare core memory stack so we were running again in a few minutes. We have traced and replaced diodes on core stacks before, so we will fix the broken core stack. We were able to format a LINCtape, but running it without a video display was a little challenging. The tape diags work better with the reformatted LINCtapes, but still not perfectly. It looks like there is an issue in the selection logic in the TU56. That should not be difficult to debug and fix. We booted LAPS6-DIAL from LINCtape. The VT14 display is not working yet, so we were driving blind. We could see some fuzzy characters displayed on an oscilloscope so we could see that our typing was actually getting handled by the editor. We tried three different oscilloscopes, but none have an intensity or blanking input so the display was not readable. We couldn't find any documentation for booting OS/12 from LINCtape, so Warren looked through an octal dump and found that block zero is the boot block, just like OS/8. The OS/12 boot block starts at 0020 like many LINC programs. Since this uses the serial console we were able to interact with the OS normally. This is the first time in 24 years that an OS has been run on this system. -- Michael Thompson

10 years, 10 months

diagnosing an Intel Series II MDS monitor failure

by spacewar＠gmail.com

A few weeks ago, while I was testing a spare IPB-80 CPU card in an Intel Series II MDS, the monitor stopped working, with the raster collapsing to a very bright dot in the center of the screen. I hit the power switch and pulled the line plug immediately, but the dot persisted for several minutes, only gradually dimming. I just started investigating it. With the monitor cable unplugged from the IOC board, the +15V DC at the IOC connector reads 0.74V. Of the two DC power supplies described in the service manual, this MDS uses the Power One. The +15V rail uses a separate transformer winding, a 723C regulator, a house-marked (12500-4) NPN pass transistor, and a zener and SCR crowbar. The 0.74V makes me think the crowbar has tripped and the 723 regulator is current limiting. Nothing else in the MDS uses the +15V supply. I was a bit lucky that this particular MDS used "method A" of installing the monitor, which makes it easier to remove. Once the metal shield is removed, the label was visible. It is a Ball Electronic Displays TV-120 monitor, which is a common enough model that it was easy to find the service manual online. I'll test the monitor on a lab power supply to see if it's drawing too much current. I may kludge up Rich Ottosen's PIC-based TV test pattern generator on a breadboard.

10 years, 10 months

Front Panel Update

by rodsmallwood52＠btinternet.com

Hi Guys The drawings for pdp8/e (A), pdp8/e (B), pdp8/f and pdp8/m have now gone to the silkscreeners for checking and costing. I'll let you all know when they are available. Those who chose to prepay but to wait for the version they needed will go out first. One issue I need to clear up. Are PDP-8/i and pdp-8/l thats (i) and (l) the same due to font ambiguity or different? For the 8/e pair I had a scan (ie done with a scanner) to work with. The /f and /m look fine but I'm very fussy about being spot on. Photos help but the sphereical abberation due to a round lens trying to photograph a square object is a problem. This together with the fact that photos are never taken at right angles to and lined up with the centre of the panel make it difficult to be absolutely shure Is there anybody there that has an /f or /m panel and a big enough scanner. Or else I'd be happy to do a new for old on a scrap /f /m panel that is still readable Rod Smallwood

10 years, 10 months

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