test-drb June 2008

test-drb@ccmp.vtda.org

194 participants
304 discussions

IBM PC/XT/AT/PS/2s and old Apricot kit up for grabs

by mikewalder＠yahoo.com

Hello fellow Computer Collectors, I have recently got married and moved house, and now no longer have the space for my computer collection: http://www.mikewalder.com/mcm.? I have found new owners for my HP and Digital kit, but still have much of the rest left.? This is all now sitting in storage, costing me ???, and the preasure to move it all is getting greater.? So, the offer is there.? If anybody on this list would like to come down to Wokingham (UK) and collect some or all of the machines, I'll be glad that they are not going on the scrapheap. I have everything on "Mike's Computer Museum" website, except the DEC, HP, Merlin, Sirius, Altos?or Exorcet stuff, I think.? But to summarize I have a large collection of IBM equipment including PCs, PC/XTs, ATs, XT/286, PS/2 model 30 (8086 ISA), model 50 (286 MCA), 55sx (316sx 16 MCA), 60 (286 MCA tower), and 80 (386DX MCA tower).?? I also have some ACT?Apricot stuff.? Drop me a mail directly at mikewalder at yahoo.com if you are interested.? I am after no money, just the willpower and time to come and collect it, and the warm feeling that they are going to someone who will make use of them. Regards, Mike Walder.

15 years, 11 months

PDP 11/34a Console dead, powersupply problem?

by asholz＠topinform.de

Hello all, just tried to power up one of my 11/34a and found it's console dead: Power on LED and adresse display are not lit. The PSU fans are running. Using the field maintenance print set for the 11/34a and docs provided at bitsavers I checked the voltages at the backplane and found the +5V Voltage seems to be out of range. Are there any docs, advices and procedures to check an repair a H7441 Powersupply? Looking at the bottom side of the PSU untit there are three PSU's, two H7441 with a red LED, the LED of one H7441 is lit, and a H755 with a bulb, which is not lit. What is the meaning of these LED and bulbs? Andreas

15 years, 11 months

Fixing a DEC Letterwriter (LA100)

by steve＠cosam.org

Hello all, I have a half-dead Letterwriter 100 KSR here I'd like to get working again. I get a short buzz from the paper feed motor at power-up but instead of flashing all it's indicator LEDs, both CTS and LINE stay illuminated. There's no carriage movement and the keyboard does nothing either. The basic vital signs are OK but I'm stuck without a service manual or schematics. Does anyone have access to these docs? I'd of course also be interested to hear of any common problems and/or things to check before I dive into all-out mending mode... Cheers, -- Steve Maddison http://www.cosam.org/ "The great thing about standards is that there are so many to choose from."

15 years, 11 months

Apple Lisa

by aek＠bitsavers.org

> I know that a Lisa sold on eBay for $10K back in '94 - eBay didn't exist in 1994 - only a Lisa I (with twiggy drives) would go for that much

15 years, 11 months

Funny Tek 2445 scope problem

by tiggerlasv＠aim.com

Not ever having seen the internals of an Imsai, I obviously can't say anything even remotely definite. However, you may see this behavior on older electronics that have capacitors between line voltage and ground. (This was popular in tube stereos and TV's for many years.) Eventually, the capacitors would leak, and you'd get a low-current tingle when you touched the chassis. Very scary. Some surge supressor circuitry is designed with MOV's between Hot-and-Neutral, Hot-and-Ground, and Neutral-to-Ground. It may be possible that you have leakage in the MOV's, and your connection to ground is weak or missing. Since it's fairly common to tie the ground to the chassis, that COULD be a source of the 60hz wave you're seeing, whether the MOV's are inside your unit, or inside an attached power strip. I would check your electrical grounds first. Also check for power supply wires hitting the chassis, or even a cable with the insulation worn through. Is the power supply a switching unit, or a traditional linear power supply ? I have two laptop power supplies, made by different manufacturers. They are two-wire (ungrounded) plugs. When plugged into my laptop, both will give me a slight tingle when I touch the metal speaker grills on the laptop, and a source of ground. Yes, metal speaker grills. It's a 233Mhz Thinkpad. ;-) It may be something inherent in the design of the switching power supplies. It might be helpful to disconnect the power supply >from the rest of the electronics, and see if you get any AC readings off of the outputs. T

15 years, 11 months

Funny Tek 2445 scope problem

by jefferwin＠gmail.com

I purchased a used Tek 2445 scope which works well on both CH1 and CH2. Both 10x probes check out as well. I am working on getting an rs232 interface working, if I scope the TX signal from my terminal I get a clean and synced image on the scope on both channels. All is good. I am rebuiding an IMSAI 8080. The unit I have is working well, 48K of RAM all tested, I can enter programs through the front panel and run them. Getting it to talk to my terminal program is the task at hand. Now comes the mystery. If I scope ANY bus line, chip lead on any board, I get a 60Hz sine wave that measures about 70 volts. Now, in my logical head I realize this can't be real, the IMSAI would not only not work but would be pouring smoke from every nook and cranny, bringing my wife running with claims of 'I told you so...'. So, what the hell? I have checked ground, I have checked the bus lines, I have checked the scope. I do have the active terminator card in the last slot and as I mentoned, the IMSAI works fine otherwise. Where am I picking up this 60hz sine wave? Thanks in advance! I love the fact that there are others out there that remember these great old machines and appreciate them for what they represent! Jeff Erwin

15 years, 11 months

Terminals ( was Re: HP 2000F' )

by kweiler＠adobe.com

Jay West - I found your 18 month old post via a Google search and wondered if you had manuals for the Micro-Term ACT-IV. I hope the email address is still valid. I have an ACT-IV but have misplaced the manual and thought it would be nice to have the complete package. Thanks! - Kevin Weiler Terminals ( was Re: HP 2000F' ) Jay West jwest at classiccmp.org <mailto:cctech%40classiccmp.org?Subject=Terminals%20%28%20was%20Re%3A%20 HP%202000F%27%20%29&In-Reply-To=> Fri Dec 22 16:38:25 CST 2006 ________________________________ Richard wrote... > What's an ACT terminal? There was a terminal manufacturer located in Saint Louis, MO around the 70's & 80's called "MicroTerm". They made quite a number of terminals that were popular across the US. As it turns out, the folks at MicroTerm had a relationship with my high school (St. Louis University High) such that they often delivered prototype and/or beta terminals free of charge or at a reduced price so that we could test them and give them feedback, find bugs, etc. Some of the terminals they made were called ACT I, ACT II, ACT IV, ACT Va, MIME 1, MIME 2, MIME 340, MIME 420, and Ergo 2000. I'm sure there were others, but those are the ones I have a manual or sales sheet or some other specific proof that they existed. I know for sure that our high school had an ACT IV as the system console (it replaced an ASR 33), and I believe the user terminals were ACT II, ACT V, and MIME 1's. In addition to these microterm terminals, we also had four LA120's and a MiniBee 4. The ACT IV was unlike the others. It was a terminal but had no crt. It had 75ohm video out that was typically hooked to a small 9" monitor. It was available assembled or as a kit. I happen to have one of these - working. With a 9" sanyo monitor, user manual, and service manual with schematics, theory of operation, etc. I would give my left arm for a Mime I or Mime II, or a Minibee 4. Oh, some time ago I looked up the VP of Engineering for MicroTerm. He sent me a nice email talking about his time at MicroTerm and he was glad someone still remembered them and their terminals. He seemed a bit surprised. I asked if he had any hardware or documentation left over, he said no. When I picked up a bunch of stuff a few years back from my high school, I got multiple copies of many of the MicroTerm manuals. I've tried seeing if there's interest in them but no one seems to want 'em. I also have a manual for the MiniBee 4. Jay West

15 years, 11 months

Epilogue Pantone or RAL reference for the blue color of the IMSAI

by chabib451＠yahoo.com

Hi everybody finally i got the cover and base of my Imsai repaint here in Switzerland. For who may be interested here are the colour references Blue Cover; NCS S 2050-B (Europe) Pantone Blue 740L Grey Base NCS S7502-B Pantone cool grey 11C Both are powder coated with structure Hope this will help someone out there Charles Habib

15 years, 11 months

invading varmints

by tiggerlasv＠aim.com

> Thank your lucky stars that you didn't suffer the fate of one of our > customers several years ago. He'd pulled out his Zorba from storage, > opened the door of the A: drive and was bitten by several irritated > brown recluse spiders that had decided to call his luggable "home". Kind of odd that he was bitten by "several" spiders, merely by opening a disk drive door. Recluses aren't at all aggressive, and generally don't go out of their way to attack. It seems highly unsual that they would "charge out in numbers", and bite. But, anything is possible. Did they manage to salvage his hand? (See link showing pictures of what a SINGLE bite will do. Note: These pictures are VERY graphic.) http://www.ascendedhealth.com/brown-recluse/bite-picture.htm We're "fortunate" enough to have both black widows, and the desert recluse here in Vegas. I'm not sure though if anyone has done any studies on the differences on the severity of the bites between the brown recluse and the desert recluse. I wouldn't be worried so much about widows; It would be unlikely to find one tucked away inside equipment, without the tell-tale sprawling tangle of spider web around it. The hobo spider of the Northwest, and the recluse of course, are different stories altogether, as they tend to wander. At any rate, back to the actual topic. ;-) If you are concerned about critters hiding inside your equipment, your first, best defense is caution. If you're in a hot-spot for venomous insects, physically protecting yourself is a good start. Wear a long sleeved shirt, and reasonably thick gloves. Make sure that your sleeve isn't exposed; tuck it under the gloves, or use some tape or other material, to ensure that nothing runs up your sleeve. If you're picking up equipment, bag it in clear plastic. That will keep critters from hopping out into your vehicle. (Watch out for static, though) Clean your equipment outdoors. If you must work indoors, then work in the middle of a large open area, preferrably with light-colored flooring. Laying down sections of white kraft paper works well. Try to establish an EMPTY 5-foot buffer zone around you. The idea is to be able to see escaping insects, before they have a chance to hide somewhere. Working on a cluttered bench is the worst idea; there too many hiding places. I honestly don't have any proven information on using insecticides inside computers / electronics. My gut tells me that it's probably not a good idea; who knows what the residue would do to the boards and components. Merely blowing out equipment with canned air isn't enough to get rid of any would-be stow-aways, either. Short of disassembly, the only other thing I could think of would be a hair dryer. I know. . . such a high-tech solution. Short-term heat from a reasonable distance shouldn't hurt any electronics, but should be enough to kill any insects, or bring them out of hiding. Component chiller would work too, although that may leave residue behind. As for any eggs, I can only recommend inspection & cleaning. T

15 years, 11 months

s100-manuals.com snatched?

by dgriffi＠cs.csubak.edu

Who had s100-manuals.com? It's now showing a generic "parked at godaddy" page. -- David Griffith dgriffi at cs.csubak.edu A: Because it fouls the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail?

15 years, 11 months

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test-drb June 2008