- test-drb@ccmp.vtda.org - classiccmp.org

Switching PSU Theory of Operation / Repair Tips & Techniques

by dhquebbeman＠theestopinalgroup.com

> > If we have a 300vdc source, positive with respect to ground, and we > > have a 300vdc source, negative with respect to ground, don't we have > > a 600vdc potential between the two sources (as long as they share a > > common ground)??? > > Absolutely. All voltages are relative to another point, and 2 300V > sources in series as you describe would, indeed, give you 600V. > > Bu what puzzles me, as I'll explain below, is where the 300V > sources are coming from. Nowhere. Ok, to make a long story short, I'm now seeing precisely the voltages you say I should see. With nothing connected to the outputs of the rectifer, I get 105vdc across the + & -. With the rectifer reconnected and the electrolytics back in place, I get just a hair under 160vdc between the caps' terminals, and just a hair under 320vdc measuring between what we're calling the +ve and -ve terminals. So, either I did in fact misread the meter, or... Well, the entire large PCB containing the secondaries is completely disconnected, removed, and set aside. In addition to the cable carrying +ve and -ve to that board, there are a few (two? I should have written that down) other cables that connect the two boards. So my only other theory is that some of what's on that board is involved in some kind of feedback process with the primary to step it up even higher. My original measurements were done with the entire PSU assembled and connected, except that it was not installed in the backplane (and thus had no load on it). It's just not going to be possible to debug it while installed in the backplane. Not in this Prime. I still intend on shooting some shots of this stuff, but yesterday someone ran off with the PCMCIA adapter for the digital film chips, as well as the only chip that didn't have important pics on it, so that has yet to take place. > > The components that I've shown as {MCI 307138} are what appear to be > > either large disk ceramic caps, or, judging by appearance, more likely > > MOVs. The one on the + side is discolored and cracked open along its > > They're thermistors. Their resistance falls when they warm up. The idea > is to limit the current that flows into the PSU via the bridge rectifier > when the supply is turned on and the capacitors are totally discharged. > Once they've charged up a bit, then the thermistors warm up, and their > resistance falls. Are you sure? My Alled Electronics catalog has thermistors, but only a few in the catalog is as large as these are- about 1 inch diameter. With everything disconnected, the on in the + circuit has 1.2 ohms resistance, the one in the - curcuit has 1.0 ohms resistance. Can you help me cross-reference that part? Any idea what manufacturer uses the initials "MCI"? Additionally, the Allied catalog doesn't carry any of those old-styled power resistors (the long, square-profile ceramic things, this one with PCB-standoff feet)... in the needed range, all they have are the newer jobs that come with a built-in heat sink. It was 15k ohms, 5%, 20 watts, made by Dale. I can get the exact part # from it tonight if needed. Wel, that's all I got at the moment. Boy, this sure is fun! regards all, -doug quebbeman

25 years, 11 months

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Chieftain or Gimix?

by foo＠siconic.com

Just curious, how many people here have Chieftain or Gimix systems? Sellam International Man of Intrigue and Danger ------------------------------------------------------------------------------ Looking for a six in a pile of nines... VCF 4.0 is September 30-October 1 San Jose Convention Center, San Jose, California See http://www.vintage.org for details!

25 years, 11 months

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Weekly finds

by mikeford＠socal.rr.com

Besides bringing home a couple VT420 and the TK50 tapes, I found some other curious stuff. SweetP nifty little plotter I used back in 1983, explitive deleted missing the pen holder, but otherwise looks OK. A LOAD of printer ribbons, boxes of a dozen, single ribbons, too many to sort just yet. I may just take a couple pictures and put the mess on my web site. DEC, QUME, Epson, NEC, a bunch, most nicely still sealed in bags. Another big box of bulk floppys (5.25"). 1/2 gallon of Medieval madness, not 10 yrs old, but I think I will go try a scoop. (4) 1 MB 32 pin simms Couple Sun IPC boxes, misc cables including a couple 13W3 to BNC adapters.

25 years, 11 months

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Assorted RSX11M-Plus manuals available

by chris＠mainecoon.com

I've a collection of RSX11M-Plus manuals available for the cost of shipping. Contact me off list if you'd like a list of what's available. -ck -- Chris Kennedy chris(a)mainecoon.com http://www.mainecoon.com PGP fingerprint: 4E99 10B6 7253 B048 6685 6CBC 55E1 20A3 108D AB97

25 years, 11 months

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Shoddy UPS service

by dhquebbeman＠theestopinalgroup.com

> Universal Package Smashers... ROFL! My first UPS experience was receiving a shipment of lab glassware (as a 7th grader!) back in '69... the burettes both arrived broken. -dq

25 years, 11 months

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Shoddy UPS service! was RE: Announcing... Rent a wreck

by dhquebbeman＠theestopinalgroup.com

> It's as ridiculous as my horror story! [..snip..] > I haven't used UPS since. While not meaning to defend UPS (whom I was once told by someone who'd done "high-level" business with them that the firm is run by hoods, and I mean hoods), it's because of problems associated with leaving packages on my front porch that I just don't do it- I have everything shipped to my place of employment. If you work in a really large firm, or don't have much juice, this might not work for you, of course. regards, -doug quebbeman

25 years, 11 months

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An alternative to UPS

by dhquebbeman＠theestopinalgroup.com

> As far as books and magazines go, it is always cheaper to ship using the > US Postal Service book rate. You must request it at the counter. In some > cases you can save up to half the shipping costs. What they don't tell you is that this is the same thing as third class postage, and when you send stuff third class, it moves from post office to post office *only* when the trucks aren't full of first and second class mail. I had a guy mail me three boxes of Prime manuals from South Carolina using the book rate; two boxes arrived in about 4 days; the third box took another week and a half before it arrived. Caveat emptor.... -dq

25 years, 11 months

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ADM 3A

by mrbill＠mrbill.net

I've got a chance to pick up one of these for $10 at a local junk shop; however, this one is BROWN - I thought they were all shades of BLUE! (or am I incorrect)? Should I even bother picking it up and hauling it out to the truck? Bill -- +-------------------\ /-----------------+ | Bill Bradford | www.sunhelp.org | | mrbill(a)mrbill.net | www.decvax.org | | Austin, Texas USA | www.pdp11.org | +-------------------/ \-----------------+

25 years, 11 months

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Using WD40 on a Remote Services Consoles

by agraham＠ccat.co.uk

Eric wrote: > Due to some idiot attempting to make their automobile occupy the same > space-time coordinates as mine, a bunch of chinese food was spilled on > my copy of the manual. Assuming that it's still legible, I'll try to > write up a summary when I find some time. *lol* - what a great description of a crash. Hope you weren't injured though! One of these days I'll get round to having another look at my Apple ///'s keyboard which was smashed in a similar incident. a

25 years, 11 months

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Shoddy UPS service

by fauradon＠mn.mediaone.net

>Now you know why UPS is called Untied Parcel Service. I thought it was United Partial Service Francois

25 years, 11 months

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Weekly finds

by dhquebbeman＠theestopinalgroup.com

> A LOAD of printer ribbons, boxes of a dozen, single ribbons, too many to > sort just yet. I may just take a couple pictures and put the mess on my web > site. DEC, QUME, Epson, NEC, a bunch, most nicely still sealed in bags. I'd be interested in some DECwriter-III (LA120) ribbons... these are the ones that look like big typewriter ribbons, just a pair of plastic reels with inked ribbon, if you have any in that batch... regardsm -doug quebbeman

25 years, 11 months

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Switching PSU Theory of Operation / Repair Tips & Techniques

by dhquebbeman＠theestopinalgroup.com

> On Wed, 26 Jul 2000 22:21:47 +0100 (BST) Tony Duell <ard(a)p850ug1.demon.co.uk> wrote: > > > The electrolytics are Mallory CGS 2900MFD 250VDC. The one on the - side > > > > And there's another clue. Those capacitors are rated for 250V, and yet > > you're seeing 280V across them. While they'd probably stand that for a > > short time, not computer power supply would be designed to work like > > that. So either there's a fault, or you're not measuring the voltage you > > think you're measuring. > > I think Tony's spotted a very strong clue, here. Kinda > makes me suspect that the voltage measurement is going > wrong for some reason. Could there be some non-DC > component that's making the meter read wrongly? With the PSU disassembled, and the secondary out of the way, I'm going to take fresh reading on the primary today at lunch. I'll post the results when I get back to the orifice, er, office. -dq

25 years, 11 months

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Switching PSU Theory of Operation / Repair Tips & Tech niques

by dhquebbeman＠theestopinalgroup.com

> Hi > I'm still puzzled over the 600V reading. My guess > is that there is a problem in the meter. As far as I know, > the inputs are usualy configured as a doubler when used > with 115V and a bridge when used for 220V. I don't > recall the circuit but I remember it was a clever trick > in that one could change it with a single jumper. I wish my Fluke was working (the LCD has gone black). I dropped my RatShack analog meter a few days back, and the needle sticks in spots, but a tap on the meter face usually frees it up. However, it measures 115v AC correctly. But, I'm going home at lunch to make a few more careful measurements of the PSU primary (the PSU is disassembled now, and I've unsoldered some parts out of the secondary PCB to test them, so we won't have any of that confusing the issue). > What a BBU? I'm assuming it's a battery backup unit. -dq

25 years, 11 months

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Switching PSU Theory of Operation / Repair Tips & Techniques

by dhquebbeman＠theestopinalgroup.com

Good Morning, All! In his last reply, Tony Duell stated (somewhere in all those quotes): > > You may not have yet seen the correction I posted, but I was seeing that > > only when I measured the + terminal of one of the blue electrolytics, and > > the - terminal of the other. Why would I do that? I'd just gotten out of > > Yes, but aren't the 2 capactiors in series, something like : > > ------------+-------------------- +ve > | > ===== > ----- > | > ------------+ > | > ===== > ----- > | > ------------+--------------------- -ve Yes. I've made a schematic of this portion of the circuit. And while I'm not very good at ASCII art, I've made a stab at it, as you can see below. > And you're seeing 600V between the 2 points I've marked '+ve' and '-ve', > right? That's still twice what I'd have expected -- I'd expect peak mains > voltage (i.e. 115*sqrt(2)) across each capacitor, or about 320V between > +ve and -ve in that diagram. > > I am still puzzled as to how it gets 600V without either other large > capacitors, or a mains-frequency transformer. If we have a 300vdc source, positive with respect to ground, and we have a 300vdc source, negative with respect to ground, don't we have a 600vdc potential between the two sources (as long as they share a common ground)??? > I will just ask again -- this thing does run off 115V, right? Yup. Now, let's talk failed components. And I suppose I'll take a stab at ASCII art by adding to what you've already "drawn": --------------------- + to BBU | | +---------{ MCI 307138 }---------------+-------------------- +ve / \ | + | / \ ===== / 12k ohm / \ ----- \ 5% / \ | - / ----* *---------------------------------+----------* | \ /| | + \ | \ / | ===== / 12k ohm | \ / | ----- \ 5% | \ / | | - | | ----------{ MCI 307138 }---------------+--------------------- -ve | | | | | | | | ---------------------- - to BBU | | | | | | 115v Load 115v Neutral In the diagram above, 'BBU' is the label on a connector to which the labeled lines run. I think it's for a Battery Backup Unit. Cool, who needs a UPS when you've got a bank of kick-ass batteries? But I digress... The components that I've shown as {MCI 307138} are what appear to be either large disk ceramic caps, or, judging by appearance, more likely MOVs. The one on the + side is discolored and cracked open along its circumferential periphery. It was blue, some of it turned green, most of it turned black. The one on the - side is discolored similarly but it not cracked open. These components are on a small board which is separate from the main PCB and which mounts by being screwed onto the tops of the two electrolytic caps. The electrolytics are Mallory CGS 2900MFD 250VDC. The one on the - side was in close proximity to a power resistor on the main PCB. The power resistor on the main PCB was a Dale 15K ohm 5% 20W unit. One leg of the power resistor is soldered to a trace which leads to what I think it the oscillator, which is one of two separate boards that plug into the main PCB. The power resistor has changed in value from 15k ohms to infinite ohms. The main PCB was discolored underneath the power resistor. The electrolytic shown above on the negative side which was in close proximity to this power resistor may have suffered some damage, as the blue plastic (heat shrink?) that Mallory uses for the CGS caps is discolored where it was in closest proximity to the power resistor. There are some other components, quite far away on the PCB from the area I've been discussing, that have also gotten hot enough to badly discolor the PCB. These components include some small 5% power resistors, two other items that look like resistors but may not be (as the color banding looks odd), and a couple of polystyrene caps. I unsoldered one of the little 5% power resistors (four of these, with little ceramic spacers/insulators on the leads, 51 ohms). It tested OK. These power resistors are nearby to two transistors (in what I think are TO-3 cases, the ones that kinda look like hats when viewed on-edge). Also, in that area of the PCB, the leads to one of the transformers have heated up and discolored the PCB underneath. A couple of other notes: The yellow AC LED appears to be lit from a signal that comes from a circuit on the main PCB that monitors the line voltage. Unfortunately, said circuit requires the DC supplies that aren't currently working. > > > > complex looking boards (although they're only 2-layer) with custom PALs and > > > > the like. > > > > > > PALs? Are you sure? It's not at all common to have significant amount of > > > digital electronics in an SMPSU. Most of the time it's either simple > > > analogue circuitry either as discrete components, or one of the well-know > > > SMPUS control chips. > > > > These look like digital boards to me. I'll pull 'em and either scan them > > Well, you've seen it, so I guess you're right. Seems a little unusual, though. > > > or take a digital photo, as well as record a few part numbers. > > If you could post the numbers on any ICs on the boards, I can see if they > make any sense. Or have they used house-numbers only ?:-( The daughter board containing the PAL has a 16L2A, IIRC. A TI part. I was told that the PSU provides a signal to the Virtual Control Panel board called "Confidence", which is like the PowerGood signal that PC switchers put out. This daughterboard may monitor the voltages and then provide that signal. That concludes my investigation to date. I'm starting to feel good about the possibility of repairing this PSU, even without the test equipment I should normally have. By replacing the obviously failed components along with the ones you and others will hopefully suggest should be replaced due to the failure of the obviously bad ones, I think this thing may damned well work again. > > > > If it matters, the room in which I keep the Prime was hotter than > > > > I usually let it get when I have the Prime running (I don't have > > > > central A/C, so I have a window unit in an adjacent bedroom and > > > > > > In which case look for dried-up (high ESR) electrolytic capacitors. This > > > is a very common heat-related problem. > > > > Would I not have to open them to make that determination? I though they > > contained PCBs or somesuch toxic chemical. > > Firstly, no, don't take the capacitors apart -- you'll ruin them if you > do. I assumed that... and I don't want to be out the US$45 a replacement would cost, but... > Measure the ESR electically -- either with a special ESR meter (the > Dick Smith Electronics one is claimed to be very good and not expensive), > or on an impedance meter. I've never used the Dick Smith meter -- I was > going to buy one and then I was given a rather nice digital impedance > meter (it applies a sine wave to the device-under-test, measures the > inphase and quadrature componentes of the current through it, and > calculates the resistance and capacitance/inductance). But I've heard > nothing but good things about said ESR meter. ...I figure the test equipment will cost more than the replacement parts. Of course, the test equipment has value beyond this one problem. :-) > Secondly, the electrolyte in these capacitors is not PCB-based (PCBs are > not electrolytes anyway...). The electrolyte is not particularly harmful. > Actually, according to somebody who works with _large_ transformers and > capacitors, yes, PCBs are dangerous _in quantity_, but unless you're > really silly, the amount in one capacitor, or even all the capacitors in > an HV PSU, is unlikely to do you any harm. I can't really comment on this > -- it's not my field. What, you mean this isn't the Classic Chemistry list? 8D Hey, I feel like we're making progress. Tony, thanks again, and to everyone, I kept this on the list rather than take it private because it just seems like someone else might benefit from it, and of course, I'm seeking input from all who'd care to contribute. regards to all, -doug quebbeman

25 years, 11 months

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Announcing... Rent a wreck

by agraham＠ccat.co.uk

Grrrrr......sassenfrassenworkinglisa2 :) > 47 Apple Lisa 2 > 48. Apple Lisa 2 a

25 years, 11 months

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Apple IIGS for parts

by agraham＠ccat.co.uk

There's a question! Which drives did the GS use - bog standard disk ][s? My GS is unused ATM since it's diskless. -----Original Message----- From: Marion.Bates(a)dartmouth.edu [mailto:Marion.Bates@dartmouth.edu] Sent: 26 July 2000 18:41 To: classiccmp(a)classiccmp.org Subject: Apple IIGS for parts Heya, First off, I apologize for sending this again -- I am losing track of what I write and who I send it to. I think I offered the drive but not the computer last time. Whatever... I have a IIGS here with a logic board problem (the "sound interrupt" issue I mentioned a week or so ago) and a bad power supply to go with it which looks and smells fine but nothing happens when you flip the switch. And yes, I checked the fuse. Got a helluva shock from one of the caps too. :-/ Anyone want these items for cost of shipping? Let me know off-list. There's even a bad 5.25 Apple floppy drive to go with it! Spins up but won't read. Thanks, -- MB

25 years, 11 months

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Back to the A1097C monitor again

by agraham＠ccat.co.uk

> actually a Sony GDM1960 (or near equivalent), and those were made in > various OEM versions for HP, Sun, Dec and possibly SGI, > differing mainly in The A1097C is a later monitor - you're thinking of the DEC VRT19 (GDM1961) that I was also considering using on the PC. > > or > > do I get nowt until my GeForce has been fully initialised > at 1280x1024? > > Yup :-) Oh well. I don't think I'll bother then, unless I get some sort of cheap monitor switch box...... cheers!

25 years, 11 months

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Vintage prices dropping on eBay?

by agraham＠ccat.co.uk

Slightly better news then; wonder why that wasn't there the last time I looked? > -----Original Message----- > From: Douglas Quebbeman [mailto:dhquebbeman@theestopinalgroup.com] > Sent: 25 July 2000 17:38 > To: 'classiccmp(a)classiccmp.org' > Subject: RE: RE: Vintage prices dropping on eBay? > > > : The History Center, originally a part of The Computer Museum > : in Boston and now located in Mountain View, California, is > : currently an applicant to become a separate non-profit > : institution. The Center plans to build a permanent Silicon > : Valley facility to house the Museum's artifact collection and > : serve as an international center for research into the > : history of computing. Last year, NASA Ames guaranteed the > : Center a long-term lease on two acres of land at Moffett > : Field, adjacent to the location of the future home of the > : California Air and Space Center. > > The home page for The Computer Museum History Center is: > > http://computerhistory.org/ > > Hoping that ends the confusion, if not the frustration, > -doug quebbeman >

25 years, 11 months

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Announcing... Rent a wreck

by dogas＠leading.net

From: Chuck McManis <cmcmanis(a)mcmanis.com> > >Of course what we've missed is that the cost of shipping of _us_ is >relatively constant. > >Further, even if I was in a position to have a really interesting computer >shipped to me as the next "hop", that wouldn't guarantee that I would get >any time at all to use it since about a million projects call out to me >from my garage every day. Finally, shipping it again and again will >continually put it at risk of damage or loss. > >The answer then suggests itself, what we need is "Classic Computer Camp." > Isn't that how the Branch Davidians started? No, I still disagree. Your forgetting the "tinker/program in your underware' factor and advantage of having *it* in your home... ;) - Mike: dogas(a)leading.net

25 years, 11 months

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Announcing... Rent a wreck

by dogas＠leading.net

>On Wed, 26 Jul 2000, Ethan Dicks wrote: >> *There*'s one I'd consider renting. The shipping would be a killer. I had > >If you think that would be bad, consider an Imsai VDP-80! BIG and >HEAVY! > - don Yeah, that one'll takes a mother's love. It's BIG, HEAVY, UGLY, MEAN. It will first have to go someone(s) who would find fixing it a challenge and joy... Cheers - Mike: dogas(a)leading.net

25 years, 11 months

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Box of TK50 and QD6150/6250 tapes

by mikeford＠socal.rr.com

I dug through about 4 moving boxes of reel tapes, and found 21 TK50 tapes (mix of some sources, some backups) and maybe a dozen QD6150 and 6250 tapes. All in nice plastic boxes. If you want a few, $1 each plus shipping, take them all for $20 and shipping. Location is Orange CA, but I will be in Palo Alto next Wed. and TRW this Sat.

25 years, 11 months

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Announcing... Rent a wreck

by dogas＠leading.net

-----Original Message----- From: Ethan Dicks <ethan_dicks(a)yahoo.com> To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org> Date: Wednesday, July 26, 2000 11:43 AM Subject: Re: Announcing... Rent a wreck > >--- Mike <dogas(a)leading.net> wrote: >> Cool. I had a few encouraging replys. Here's the first list of available >> stuff... >> >> 14. OSI CIII > >*There*'s one I'd consider renting. The shipping would be a killer. I had >a family friend when I was a kid that had one of these at home. ISTR it was >around $8-$10K, loaded. I did some BASIC and assembler on the 6502 side. I also have a few extra 510(I think) boards with the 3 mp's that would go in alot of other OSI stuff, so maybe shipping what ya need can be customized/economized... >What are your terms? Would you consider "payment in kind" in the form of >an equipment exchange? Wonderful idea! >Also... consider writing up a formal contract that >spells out rights and responsibilities, especially for loss or damage. I'm >not so much concerned that the people on this list will try and rip you off, >but if an insurance claim ever needs to be filed due to fire, theft, etc., >the renter's insurance company will be more likely to honor the claim if >there's a paper trail establishing liability (take it from someone who has >had to seek coverage of stolen classic computers - two PETs and an Amiga). > Yup, good ideas too. can anyone suggest other items needing covered? And, I'm located in Florida, USA. So, maybe if others (like Sellam (nudge)) also offer items, shipping can be arranged from the closest offerer... Cheers - Mike: dogas(a)leading.net

25 years, 11 months

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OSI model 600 find

by dogas＠leading.net

-----Original Message----- From: Joe <rigdonj(a)intellistar.net> To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org> Date: Wednesday, July 26, 2000 8:05 AM Subject: Re: OSI model 600 find >At 02:40 PM 7/25/00 -0700, Doug wrote: > >>All in all it looks to be in very good condition, >>but powering this up is going to have to wait. My >>wife wants my current projects off the dinner table >>and the analog flight simulator and the paper tape >>punches out of the dining room. > > Wifes, they just don't understand. My wife wants my HP 9845 and 9895 >dual 8" drives out of the kitchen. I have no idea why :-) > > Joe Heh, *ex* wifes begin to get the picture... ;) - Mike: dogas(a)leading.net

25 years, 11 months

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Announcing... Rent a wreck

by dogas＠leading.net

Nope. Still looking for them too. There were a few ads in some old Kilobauds that give some generalities but that's about it. I'll let you know when/if I find them. Cheers - Mike -----Original Message----- From: allisonp(a)world.std.com <allisonp(a)world.std.com> To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org> Date: Wednesday, July 26, 2000 10:24 AM Subject: Re: Announcing... Rent a wreck > > >On Wed, 26 Jul 2000, Mike wrote: > >> 6. Imsai 8048 > >Do you have docs????? I have a working one but would love to get a >manual. > >Allison >

25 years, 11 months

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TI Silent 700 terminal

by paulrsm＠ameritech.net

I just picked up a TI Silent 700 terminal from a local college. It has the keyboard, printer with some paper, acoustic coupler, and cover. I have not even tried to turn it on yet so I do not know if it works. 745 Portable Part number: 0983801-0003 Serial number: 0474656335 Volts: 120 VAC Freq: 47-63 Hz Amps: 1.0 A Watts: 75 W Paul R. Santa-Maria Ann Arbor, Michigan USA paulrsm(a)ameritech.net

25 years, 11 months

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M840 omnibus High Speed papertape reader/punch

by lemay＠cs.umn.edu

Does anyone have any documentation on the M840 high speed paper tape reader/punch board for the PDP 8/e? I'm wondering what I can connect it to, can it be connected to a more modern serial reader/punch, etc? -Lawrence LeMay

25 years, 11 months

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PDP 8/e power wires

by lemay＠cs.umn.edu

My PDP 8/e has its power cable cut off. The wires are color coded White, Black, Green. This is for a Dec H724 power supply. Does anyone have any schematics or doc that would tell me how to connect those 3 wires to a power plug? Its about time I powered this thing up to see if the capacitors are working. I dont have an electronics test bench, so i'll just have to pull the boards out and turn it on, and hope for the best. -Lawrence LeMay

25 years, 11 months

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CCC (was Re: Announcing... Rent a wreck)

by ethan_dicks＠yahoo.com

--- Chuck McManis <cmcmanis(a)mcmanis.com> wrote: > Of course what we've missed is that the cost of shipping of _us_ is > relatively constant. True, but more than some boxes. > The answer then suggests itself, what we need is "Classic Computer Camp." > > We find some very cheap land somewhere that has relatively easy air access > (somewhere in New Mexico perhaps) and we build a camp. At the camp we have > a bunch of buildings with computers in them and a dorm. Enthusiasts from > all over the world can fly to the camp, and for a modest fee, spend as much > time as they can afford tinkering with all kinds of classic computers. If > it was a self sustaining operation I'd suggest we convince Tony to relocate > to be in charge of the camp, that way he could be employed at a job where > all day all he had to do was tinker with and fix old computers and talk to > people about how they worked while they tinkered with them and fixed them. > > This solves a number of problems: > 1) Cost effective storage (since you can get 50 acres in New > Mexico for $25,000 easy) > 2) People get to play with the computers, they don't have to deal > with the outside world. > 3) The assortment could be much larger (even "big" iron!) > 4) We enough lead time it would be cost effective to travel there. > > I suspect several people would be more than happy to contribute large > numbers of computers to this effort. Well... I already have 32 acres and a quonset hut. I have plans to add a large building (40'x60' nominally) next door to it, but I'd have to upgrade my electrical service first. I'm in Columbus, OH, a few minutes away from Port Columbus with direct service from most major hubs (Chicago, NYC, DFW, Atlanta, DC, St. Louis, Phoenix). I'm 8 hours or less by car from Toronto, Pittsburg, DC, St Louis, Chicago, Nashville (I think), and a host of other places. Benefits: Well located for midwest and East Coast users (especially me ;-) Land already grabbed Zoned Rural, not Residential (a "library" is an acceptable use) Well stocked with VAXen on down. Drawbacks: Colder than N.M., therefore higher operating costs (heat, etc.) Smaller than 50 acres. Far from West Coast Users. I have this 501c3 Museum project that I've been working on for a while, but frankly, I'm kinda stalled out at the name phase. I have the necessary number of enthusiastic bodies to incorporate non-profit in Ohio (three), all I really need to do is pick a name, finish off the articles of incorporation and pay the filing fee. It's easy to self-serve an Ohio corp; it's the second best state next to Delaware. At least in the non-winter months, it'd be easy to provide camping-style accomodations (including parking for RV, for those so inclined). Actual housing is another level of expense, no matter what the location. It's certainly an interesting concept. Actual implementation is another matter entirely. Classic Computer Camp or no, my 10-year-plans are to stick up a suitable building for my own uses. Finding a way for the construction and operation to be even partially funded would be a bonus. -ethan ===== Even though my old e-mail address is no longer going to vanish, please note my new public address: erd(a)iname.com The original webpage address is still going away. The permanent home is: http://penguincentral.com/ See http://ohio.voyager.net/ for details. __________________________________________________ Do You Yahoo!? Get Yahoo! Mail - Free email you can access from anywhere! http://mail.yahoo.com/

25 years, 11 months

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Switching PSU Theory of Operation / Repair Tips & Techniques

by dhquebbeman＠theestopinalgroup.com

[..snippage..] > > No, if I measure across the positive and negative, I'm seeing nearly 600vdc. > > Eeek!. That's double what I'd have expected. Does this thing run off the > normal 115V mains, or 220V? How does it (effectively) quadruple the mains > input? [..more snippage..] > > : switcher, which runs the 280V DC through the torroidal transformers to > > : produce the other voltages. The Big Bridge is to convert the output of the > > That's more what I'd have expected. About 300V supply to the chopper > stage, not 600V. > > Can I ask a silly question? Are you sure you're reading the voltmeter > correctly. You've not got a 'range doubler' turned on or something (I've > been caught by this one...) You may not have yet seen the correction I posted, but I was seeing that only when I measured the + terminal of one of the blue electrolytics, and the - terminal of the other. Why would I do that? I'd just gotten out of bed and hadn't had coffee yet. YES, A BAD TIME TO MESS WITH HT! After I saw that I realized my time would be better spent letting the dog out and preparing to leave for the office rather than risking my life while I was still half asleep. No more messing with it except when alert, I promise! > > > ****PAGING TONY DUELL**** > > Did you honestly think I'd not reply to a question like this :-). Be sure to check the quote level to see that this wasn't me who said it. > > I can probably sketch the HT portion out, but this PSU includes two rather > > complex looking boards (although they're only 2-layer) with custom PALs and > > the like. > > PALs? Are you sure? It's not at all common to have significant amount of > digital electronics in an SMPSU. Most of the time it's either simple > analogue circuitry either as discrete components, or one of the well-know > SMPUS control chips. These look like digital boards to me. I'll pull 'em and either scan them or take a digital photo, as well as record a few part numbers. Keep in mind that being overly proprietary was one of the things that killed Prime. > > One symptom I hope leads me to finding the problem is that the PSU has > > four LEDs onit, 3 green, 1 yellow, the green are status indicators for > > +5, +12, & -12; the yellow LED is an indicator for the AC. Although the > > AC feed to the PSU is fine, the yellow LED glows dimly, not brightly, as > > it once did. The green LEDs are unlit. > > That's a starting point. Trace back from that 'AC' LED to find what it's > really monitoring. Maybe that supply line is low. > > > That suggests that the mains rectifier is still functional, they don't > > > 'chop' the ac mains. > > > > Uh, being an analog idiot, forgive me if this is a stupid remark, but > > I thought "chopping" the AC with a rectifier yielded DC; when I measured > > No. 'Rectifying' is turning AC into DC. 'Chopping' is turning that DC > back into a square wave (at least in voltage, as I mentioned last night, > the current waveform is complex). Ok. I thought chopping referred to the way the waveform looks before vs. after. Before it's a sine wave, crests about and below the axis. After being rectified, there are only crests above the axis. That looks like chopping off the bottom part of the wave to me. Sorry. > > If it matters, the room in which I keep the Prime was hotter than > > I usually let it get when I have the Prime running (I don't have > > central A/C, so I have a window unit in an adjacent bedroom and > > In which case look for dried-up (high ESR) electrolytic capacitors. This > is a very common heat-related problem. Would I not have to open them to make that determination? I though they contained PCBs or somesuch toxic chemical. regards, -doug q

25 years, 11 months

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Using WD40 on a Remote Services Consoles

by jfoust＠threedee.com

WD40 is a pretty good fire starter. - John

25 years, 11 months

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Switching PSU Theory of Operation / Repair Tips & Techniques

by dhquebbeman＠theestopinalgroup.com

Geoff Roberts stated thusly: > This is starting to sound like it has either a separate + and - supplies with a common ground, or > it's some kind of voltage doubler. Since I can't imagine why they'd need to do a doubling act > for the primary side of a SMPS I'm inclined to suspect the former. Here's a quote from a former Prime engineer (who's been as helpful as his memory permits): : These things are much more complicated than that. Functionally the Line is : directly connected to a special rectifier configuration called a voltage : doubler. It produces rougly 280 volts DC. There is no isolation transformer, : which makes these things potentially lethal. The 280V DC is input to : switcher, which runs the 280V DC through the torroidal transformers to : produce the other voltages. The Big Bridge is to convert the output of the : switch from high frequency (probably about 25Khz) AC to DC. Howwver, your former remark would also seem to be true, as the two rectifer outputs are +280vdc and -280vdc, respectively. [..snippage..] > > Yes, but aren't the 2 capactiors in series, something like : > > > > ------------+-------------------- +ve > > | > > ===== > > ----- > > | > > ------------+ > > | > > ===== > > ----- > > | > > ------------+--------------------- -ve > > Well they could be if they were across a potential higher than the invidual voltage rating of the caps. > That gives you an effective voltage rating equal to the sum of the ratings of the caps. The penalty is > that it divides the effective capacitance by the number of caps in the series circuit (assuming all are the > same value - it's a bit more complex if they have different values) Have you got a + where there should be -? > The above diagram looks wrong to me. If this was a +/- supply, then the lower cap should have it's anode > connected to the common (centre) ground point, or it's effectively reverse polarised. It would be more > common to find caps in parallel to increase the capacitance (opposite of series - the total c of the > circuit is equal to the sum of the values of all the caps in it.) > > > And you're seeing 600V between the 2 points I've marked '+ve' and '-ve', > > right? That's still twice what I'd have expected -- I'd expect peak mains > > voltage (i.e. 115*sqrt(2)) across each capacitor, or about 320V between > > +ve and -ve in that diagram. > > The Prime techie mentioned a bridge, so I assume it's not a doubler circuit, > that leaves some kind of +/- supply but I'm blowed if I know how they achieve that > out of a bridge. I'd definitely like to see a circuit for this one. > > > I am still puzzled as to how it gets 600V without either other large > > capacitors, or a mains-frequency transformer. > > Ditto. --------------------- + to BBU | | +---------{ MCI 307138 }---------------+-------------------- +ve / \ | + | / \ ===== / 12k ohm / \ ----- \ 5% / \ | - / ----* *---------------------------------+----------* | \ /| | + \ | \ / | ===== / 12k ohm | \ / | ----- \ 5% | \ / | | - | | ----------{ MCI 307138 }---------------+--------------------- -ve | | | | | | | | ---------------------- - to BBU | | | | | | 115v Load 115v Neutral > > I will just ask again -- this thing does run off 115V, right? > > I keep wondering the same thing, if it was multiphase it might make sense, hmmm, > I *wonder* if this was originally 3 phase and been converted to single? > 2 mains rectifiers in series? With a common rail? Sounds ugly but possible I suppose. There is an adhesive label on the front of the PSU that says "115 V". Since it's a removable label, that there is some way to change it over for 230v operation. With that in mind, I can report that there is a connector on the main PCB that has wires that loop back to itself. I'm wondering if it's replaced with a plug either without wires or with wires in a different configuration that it changes the PSU from accepting 115v input to 230v input. But about phases, I am very ignorant. [..snip-o-rooney..] > > > > PALs? Are you sure? It's not at all common to have significant amount of > > > > digital electronics in an SMPSU. Most of the time it's either simple > > > > analogue circuitry either as discrete components, or one of the well-know > > > > SMPUS control chips. > > How old is this box of tricks anyway? I must agree, if there is a lot of logic there, > from the description of all the led monitoring etc, it might be more to do with that than > part of the supply proper. Possibly control logic to ensure the system won't power > up if the supplies are out of spec, or shutdown the whole thing if one fails etc... I think this is correct. > > > > In which case look for dried-up (high ESR) electrolytic capacitors. This > > > > is a very common heat-related problem. > > Indeed. Probably the commonest fault in PSU's, which tend to get pretty hot > anyway. The startup resistor is still a potential culprit here too. Geoff, see my other post which is a reply to the same message to which you were replying in this message to which I was replying. [hope that's clear!] regards, -doug quebbeman

25 years, 11 months

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Using WD40 on a Remote Services Consoles

by ethan_dicks＠yahoo.com

--- Eric Smith <eric(a)brouhaha.com> wrote: > I know nothing about the standalone RDC box that's been discussed earlier. > But the 11/70 didn't use that. It used a replacement front panel (without > the usual switches and lights) and a Unibus board. IIRC, it was called > a KY11-R. That's what I've got. :-( I would love to have switches and lights on an 11/70 but I doubt I'll ever find an affordable older panel. -ethan ===== Even though my old e-mail address is no longer going to vanish, please note my new public address: erd(a)iname.com The original webpage address is still going away. The permanent home is: http://penguincentral.com/ See http://ohio.voyager.net/ for details. __________________________________________________ Do You Yahoo!? Get Yahoo! Mail - Free email you can access from anywhere! http://mail.yahoo.com/

25 years, 11 months

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Using WD40 on a Remote Services Consoles

by cmcmanis＠mcmanis.com

Ok, I'm completely baffled. Is there some sort of conspiracy afoot to not discuss how the DEC remote services console works or is used? I know that there are ex-DEC field service types here and certainly ex-Digits who should know the basics. And yet at least three times over the last 2 years theses questions have come up and been left hanging with absolutely no information. Whazzup wit' dat? I happen to have a use for mine that is exactly what was intended, I've got a VAX 4000/300 sitting at my office that I'd like to be able to dial into the console and reset and reboot. I don't have a spare serial port on a PC to use and it would be "cool" to do it with this piece of vintage gear that was designed to do this. Yes, I know these things were originally DEC proprietary and secret stuff but heck DEC is dead. We've got to keep this information alive, not let Compaq take it to the grave with them. --Chuck

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Announcing... Rent a wreck

by ethan_dicks＠yahoo.com

--- Mike <dogas(a)leading.net> wrote: > Cool. I had a few encouraging replys. Here's the first list of available > stuff... > > 14. OSI CIII *There*'s one I'd consider renting. The shipping would be a killer. I had a family friend when I was a kid that had one of these at home. ISTR it was around $8-$10K, loaded. I did some BASIC and assembler on the 6502 side. > 21. Kim-1, Kim-4, TVT, etc... Cool... I happen to have a TVT that I've never powered on. I built it as a kid and never got the 6502 SBC to hook it up to. > 44. Cosmac ELF-II > 45. Cosmac SuperElf I'd love to play with these, too. I have just about every other 1802 box of the era, including the Radio Shack video game (supposedly upgradable to a full computer) and a VIP terminal. What are your terms? Would you consider "payment in kind" in the form of an equipment exchange? Also... consider writing up a formal contract that spells out rights and responsibilities, especially for loss or damage. I'm not so much concerned that the people on this list will try and rip you off, but if an insurance claim ever needs to be filed due to fire, theft, etc., the renter's insurance company will be more likely to honor the claim if there's a paper trail establishing liability (take it from someone who has had to seek coverage of stolen classic computers - two PETs and an Amiga). -ethan ===== Even though my old e-mail address is no longer going to vanish, please note my new public address: erd(a)iname.com The original webpage address is still going away. The permanent home is: http://penguincentral.com/ See http://ohio.voyager.net/ for details. __________________________________________________ Do You Yahoo!? Get Yahoo! Mail - Free email you can access from anywhere! http://mail.yahoo.com/

25 years, 11 months

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Creating Schematics for Old Computer Circuitry: CAD Freeware

by dhquebbeman＠theestopinalgroup.com

Well, I seriously doubt I'd end up want to CAD an entire PSU, but habing to struggle making an ASCII art schematic this morning got me thinking about CAD freeware again. I work for an architectural firm, and have AutoCAD installed on my workstation, but I don't have a symbol library of electronic parts, so I haven't bothered trying to use it for electronics. I do have PADS*PCB, which is available as either a commercial product or as crippleware (something like 60 components). I was just starting to get pretty gppd with it when I had to shelve the project I was working on for work that had regular paychecks. Does anyone know of/use a freeware CAD program for producing moderately-complex schematics? Something a bit less than what you'd need to create the typical modern PC motherboard (although VLSI seems to have taken some of the complexity load off the motherboards)? I really don't even need PCB component layout or autorouting, just a nice schematic program. tia, -doug quebbeman

25 years, 11 months

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OSI model 600 find

by mranalog＠home.com

Bill Sudbrink said: > > The main board says: > > "Ohio Scientific Model 600 CPU @1978 Rev B" > > I can give you full schematics for this guy. I've got the > SAMs. I'm in no hurry. Thanks for the offer, but you just finished supplying me with all that documentation on the C4P. Someone just down the street from me says he has documentation and schematics for the mother board. I'll check that out first. He also pointed me to a couple of great Compukit 101 pages: http://www.compukit.org/ http://www.home-micros.freeserve.co.uk/uk101/uk101.html > > The small daughter board contains three 2716s labeled > > "REV 94 I", "REV 94 II", and "REV 94 III". > > I think that's an Aardvark board too... no idea what's on the > EPROMs though... Looking closer, there are sockets on the mother board for 8 pairs of 2114s. There is one pair of 2114s in the first pair of sockets and one pair of 2114s in the last pair of sockets. It looks like the select lines for the 6 pairs of sockets inbetween are wired to these 2716s. So it has the feel of some kind if firmware application. Joe <rigdonj(a)intellistar.net> said: > Wifes, they just don't understand. My wife wants my HP 9845 and 9895 >dual 8" drives out of the kitchen. I have no idea why :-) If she didn't understand, then the drives never would have made it to the kitchen. I'm sure she just wants to make sure she doesn't stumble into the kitchen one morning and stick a Pop-Tart into one of your drives. In your house there is a path through the garage, a path through the living room, a path through the dining room, and one bedroom that I can just look into. My wife just wants a corner in the dining room to set-up a trendmill. --Doug ==================================================== Doug Coward dcoward(a)pressstart.com (work) Sr. Software Eng. mranalog(a)home.com (home) Press Start Inc. http://www.pressstart.com Sunnyvale,CA Curator Analog Computer Museum and History Center http://www.best.com/~dcoward/analog ====================================================

25 years, 11 months

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Using WD40 on a Remote Services Consoles

by dhquebbeman＠theestopinalgroup.com

> > WD40 is a pretty good fire starter. > Don't know about fire per se, but on this list, it's certainly started a flame or two... 8D

25 years, 11 months

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OSI model 600 find

by dhquebbeman＠theestopinalgroup.com

> In your house there is a path through the garage, a path through > the living room, a path through the dining room, and one bedroom > that I can just look into. My wife just wants a corner in the > dining room to set-up a trendmill. ^^^^^^^^^ ROFL! I vote that to be the best malapropism of the year 2000! 8D

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VT420 Keyboards in Kansas City

by mmcfadden＠cmh.edu

Our hospital surplussed all of our DEC terminals of which I "found" a few. Later I found the extra keyboard stash and they donated them to me. They appear to be in good shape if anybody wants one or two keyboards for personal use I'll send you one. We can work out shipping and payments methods. I'm not auctioning them just willing to donate them for shipping and a dollar or two. Mike mmcfadden(a)cmh.edu

25 years, 11 months

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Using WD40 on a Remote Services Consoles

by dhquebbeman＠theestopinalgroup.com

> Yank corporations (and citizens to a somewhat lesser extent) seem to live(?) in eternal > terror of being sued by someone for something they have done or not done. > This impedes the free distribution of much knowledge and hardware that has no > further commercial value. I'm on Shakespeares side. "First, lets kill > all the lawyers." Now, now... let's not attribute to Shakespeare every attitude contained in a remark made by one of his literary characters... we'd have to view him as a pretty schizoid individual if we did! > Just my 2c worth. If I was a lawyer, this opinion would probably have > cost you $100. ROFL! -dq

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VT420, only toasted

by dhquebbeman＠theestopinalgroup.com

> Some of the units have a velcro attached glare screen, most have a short > dongle with a weird RJ11 socket. There were also a few VT320 displays, but > I haven't looked that closely at them (same burnin look though). This > Thursday will likely be my last chance at them, as a big load is coming in > that day, and I will be in Silly Con Valley (yes really) next week (8/1 to > 8/3). The "dongle" is most likely one of many RS_232-to-twisted_pair adapters that many sites use for connecting terminals to a comm system. I have a few that use RJ-45s instead of RJ-11s; one end plugs into a serial port on the comm system, then you run this preassembled phone-line-like cable >from there to an identical unit plugged into the back of the terminal. Drives my Wyse-50 very nicely on the Prime's ICS3 subsystem; at least, it did when the Prime's PSU was working. :-( -doug q

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Announcing... Rent a wreck

by dogas＠leading.net

Cool. I had a few encouraging replys. Here's the first list of available stuff... 1. SWTPC 6800, CT-64, AC-30, PR-40 2. SWTPc 6800 3. SWTPc 6809 4. SWTPC S/09 5. Imsai 8080 6. Imsai 8048 7. Imsai VDP-40 8. Imsai VDP-80 9. OSI 500 10. OSI 600 11. OSI CII, C2D 12. OSI CIIC12 13. OSI C2-OEM 14. OSI CIII 15. Northstar Horizon 16. Northstar Advantage 17. Exidy Sorcerer, S100 Expansion box, parts 18. Homebrew (Thinker Toys s1000), 2 8' drives 19. Homebrew 'The Puzzle' 20. Kim-1 21. Kim-1, Kim-4, TVT, etc... 22. Sym-1 23. Sym-1 24. Aim-65, Basic roms 25. Aim-65, assembler 26. Aim-65 37. HP-5036, logic probes 38. HP-5036 39. HP 5036 40 Amd 2900 EVB, 4-bit CPU 41. Motorola MEK-6800d2 42. Little Professor MPF-1 43. Cosmac ELF 44. Cosmac ELF-II 45. Cosmac SuperElf 46. MITS Altair 680 47 Apple Lisa 2 48. Apple Lisa 2 49. Apple /// 50. Apple Newton 2100, Keyboard 51. Canon Cat, Printer 52. Heathkit ET-3400, ET-3401 6800 Training courses 53. Heathkit ET-3400, ETA-3400 54. Heathkit H-8, H-17, H-19 55. Heathkit H-8, H-17 56. Heathkit H-11, H-27 57. Heathkit H-89 58. Heathkit H-89 59. Heathkit Z-100 60. Vector 3, HD 61. TRS-80 Model 1 and stuff 62. TRS-80 Model 1 63. TRS-80 Model 1. 64. TRS-80 Model 4p 65. TRS-80 Model II 66. TRS-80 Model 6000, 35mb HD, Xenix 67. Commodore PET 2001-8K 68. Commodore PET 4008 69. Commodore PET 4032 70. Commodore CBM 8032, 4040 Floppies 71. DEC PDP 11/05 mini 72. Honeywell 316 mini 73. S100 EPROM programmer 74. S100 Disk Jockey Let me know if you want to play. Thanks - Mike: dogas(a)leading.net

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Dinner Table Diagnostics (Was: RE: OSI model 600 find)

by dhquebbeman＠theestopinalgroup.com

> All in all it looks to be in very good condition, > but powering this up is going to have to wait. My > wife wants my current projects off the dinner table > and the analog flight simulator and the paper tape > punches out of the dining room. I'm glad someone else does this; well, I used to use the dining table in my mother's home (which is now mine, but I don't currently have a dining table in or any other in the dining area)... these days any level surface is fair game, even the bed (which is where part of my PSU is currently residing). -dq

25 years, 11 months

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OSI model 600 find

by dogas＠leading.net

From: Doug Coward <dcoward(a)pressstart.com> Subject: OSI model 600 find > It's been a while since I have picked-up any _digital_ >computers, but I just could not resist this. I found >someone selling a Ohio Scientific Model 600 on eBay, >and when I went to check was it sold for, I discovered >that no one wanted to bid the $20 minimum bid. > >http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?MfcISAPICommand=ViewItem&item=3758 5 >7886 > >So I asked for a picture of the computer to make sure it >wasn't just a baggie full of spare parts. > >http://www.best.com/~dcoward/osi600.jpg Nice find on the 600 (the Superboard II or naked C1P.) Cool Aardvark card too! Maybe its a 3'd party 630 clone, the backright lookes like a whipped up A15. Congrats. - Mike: dogas(a)leading.net

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VT420, burned

by ethan_dicks＠yahoo.com

--- Mike Ford <mikeford(a)socal.rr.com> wrote: > >Picture tubes can be replaced, so hang on to the VT420's! > > There is a good pallet load of them, and so far ZERO interest from this > list... I would love a VT420; I would not love to pay to ship one across the U.S. If I found a pallet of them locally, I'd grab it. -ethan ===== Even though my old e-mail address is no longer going to vanish, please note my new public address: erd(a)iname.com The original webpage address is still going away. The permanent home is: http://penguincentral.com/ See http://ohio.voyager.net/ for details. __________________________________________________ Do You Yahoo!? Get Yahoo! Mail – Free email you can access from anywhere! http://mail.yahoo.com/

25 years, 11 months

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pardon

by dogas＠leading.net

Although I didn't intend it that way, my last post sounded kinda spammy when I received it, and I apologize if it did to you too. Cheers - Mike: dogas(a)leading.net

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PDP-11/34A

by xds_sigma7＠hotmail.com

Hi, I have an 11/34A, and I'm also trying to help a friend (who is out of state) put his back together, since its totallly dismantled. Unfortunately, neither of us has any manuals for it... But more importantly, we're not sure how the PSU is supposed to be set up.. here's a little cruddy drawing of how it is on mine: i-----i i-----i i------------i i i-----i i-----i i P16 i i P15 i i Big conn. i i i P14 i i P13 i i----i i----i i---i i---i----i i----i i i i i Big ol' i i i i H745 i H744 i Transformer, etc. i H7441 i EMPTY i i -15V i +5V i i +5V i i i 10A i 25A i i 32A i i i i i i i i i i i i i i i__________i__________i____________________i__________i__________i Key: The P numbers are the connectors where the power supply meets the wiring harness, so the diagram is viewed from the top, with the P connectors on the front. Left is left, and right is right. Anyway, please let me know ASAP! Also wouldn't mind the printset ;p or the FPP manual... Will J ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com

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Vintage prices dropping on eBay?

by agraham＠ccat.co.uk

I got a reply from one Max Burbank who said only this - "While the Computer Museum has closed, We have incorporated some of it's exhibits and it's mission into our own. For all the details, Follow this link; " and he gave a link to the Computer Section of the Boston MOS, which ultimately came up with nowt to say what had happened. Here's the link: http://www.mos.org/tcm/tcm.html > -----Original Message----- > From: John Honniball [mailto:John.Honniball@uwe.ac.uk] > Sent: 25 July 2000 16:13 > To: classiccmp(a)classiccmp.org > Subject: Re: RE: Vintage prices dropping on eBay? > > > > On Tue, 25 Jul 2000 15:25:36 +0100 Adrian Graham > <agraham(a)ccat.co.uk> wrote: > > Not any more - the Boston Computer Museum closed in July > '99 and some of it > > was 'merged' with the Science Museum. > > Indeed so. > > > I only found out when I went to the > > Children's Museum, which was next to the Computer Museum.....most > > disappointed I was. > > Fortunately, I found out just before my visit to Boston in > September 1999. > > > I mailed them afterwards asking what had happened > > and all they could say was the collection still exists. > > Helpful, that. > > Hasn't it been shipped to California? The Computer Museum > History Centre? Moffat Field? Or am I getting confused? > > -- > John Honniball > Email: John.Honniball(a)uwe.ac.uk > University of the West of England >

25 years, 11 months

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Announcing... Rent a wreck

by dogas＠leading.net

Hi Gang, I think I hit on an idea that will help out me and others... Want to try a *old* computer before you buy one? Want to run some old software or access some old data from a computer you no longer have? Want to try your skill makeing some necessary repairs on some vintage computers? Want to try programming when programming was programming? I'm thinking something like a month or two rental, paying for shipping to get it to you. (Next person in line ships from renter(n-1). I'll pay to eventyally get it back to me. This will put machines in circulation, clearing some needed space, and it allow me to better schedule the time I want with any particular machine. Waddayaall think? Would you rent an old machine you haven't found yet? There's certainly a few I wouldn't mind buying time on.

25 years, 11 months

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Vintage prices dropping on eBay?

by agraham＠ccat.co.uk

Not any more - the Boston Computer Museum closed in July '99 and some of it was 'merged' with the Science Museum. I only found out when I went to the Children's Museum, which was next to the Computer Museum.....most disappointed I was. All it's been replaced with is a handful of multimedia Compaqs and some iMacs. I mailed them afterwards asking what had happened and all they could say was the collection still exists. Helpful, that. > -----Original Message----- > From: Bob Withers [mailto:bwit@pobox.com] > Sent: 25 July 2000 14:44 > To: classiccmp(a)classiccmp.org > Subject: Re: Vintage prices dropping on eBay? > > > At 12:21 AM 7/25/00 -0000, you wrote: > >> Related note: Anybody on the list know anything > >> on DEC's first product, the Lab Module series? > >> I'm interested in the operating principles of > >> the things. > > > >You need the book _Computer Engineering: A DEC View of > Hardware Systems > >Design_, by C. Gordon Bell, J. Craig Mudge, and John E. > McNamara. Out > >of print, but usually not too hard to find. > > > >It's available online at > > > > > http://www.ulib.org/webRoot/Books/Saving_Bell_Books/Computer_E ngineering/con tents.html > >But this is definitely a good book to have in one's library in dead-tree form. > When I was in Boston a couple of years ago I bought a copy of this book at the BCS Computer Museum gift shop. I don't know for sure if it's new but it certainly looks it. If someone is in the area it might be worth checking out. Regards, Bob -------------------------------------------------------- "If you pick up a starving dog and make him prosperous, he will not bite you. This is the principal difference between a dog and a man." -- Mark Twain

25 years, 11 months

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