test-drb July 2007

test-drb@ccmp.vtda.org

189 participants
323 discussions

Classic phone repair (was Re: 1966 Mag: Build NE-2....)

by classiccmp＠memory-alpha.org.uk

Hi, > As expected, while you get an overall schematics of the phone, >there are no internal schematics for the dialer (keypad/DTMF >econder) or ringer. May be some help, though. On the contrary, that looks like exactly what I was looking for (unless the fault is in the keypad unit, LOL). Many thanks. TTFN - Pete.

16 years, 12 months

Three "classic" printers (and a PC) available for free (UK)

by classiccmp＠memory-alpha.org.uk

More stuff to get rid of.... I've got an HP "Laserjet+", a DEC "LA324 MultiPrinter" and an Epson "FX-1170" available for the cost of coming and picking them up from Birmingham. The Epson printer also comes with a free Tandon "Pac 286" AT clone, c/w keyboard and mono monitor (Hercules?) and there might even be a manual or two. It's one of the models with no internal FD and contains two "data pac" receptacles, there's one data pac included (10Mb I think). Never powered any of this stuff up, but it was all working when I received it. Drop me a line off list in interested, thanks. TTFN - Pete.

16 years, 12 months

Advice/Suggestions for repairing Apple III power supply

by derschjo＠msu.edu

Hi all -- Picked up an Apple III this weekend in non-working condition, and I suspect the power supply is at fault. Symptoms are: On power up, a rapid clicking noise is emitted from the power supply (maybe 4Hz or so), and the power LED on the system's motherboard pulses at the same rate. Obviously I haven't run it for more than a few seconds like this :). There are no obviously bad parts (burned parts, swelled/leaking capacitors, etc...) that I can see. I'm mostly a software guy but I'm trying to get more into hardware so that I can better maintain my collection as more stuff starts to break down :). I'd like to make an attempt to fix this but I'm unsure where to start. I have found schematics at: http://www.1000bit.net/SUPPORT/SCHEMA/a3/050-0057-a.jpg. If anyone has any advice, I'd be most appreciative. Thanks in advance! - Josh

16 years, 12 months

Interesting document listing characteristics of pre-1971 spaceborne computer systems

by wbblair3＠yahoo.com

Spaceborne digital computer systems, NASA SPACE VEHICLE DESIGN CRITERIA (Guidance), NASA (Washington, DC, United States), March, 1971, pp. 82, Format(s): PDF 10187k http://trs.nis.nasa.gov/archive/00000106/ ____________________________________________________________________________________ Looking for a deal? Find great prices on flights and hotels with Yahoo! FareChase. http://farechase.yahoo.com/

16 years, 12 months

Classiccmpers near Dusseldorf?

by cheri-post＠web.de

Hello Ethan, I am from Bonn, which is an hour away from D?sseldorf. Tell me when you're going to be there. Although I don't have much time at the moment, it maybe it's possible to meet in D?sseldorf. Regards, Pierre > Are there any list members in or around Dusseldorf or Wuppertal? It > looks like the University is sending me there for a few days in > August. I've spent plenty of time in Munich, but don't know much > about other parts of Germany. > > Cheers, > > -ethan > _______________________________________________________________________ Jetzt neu! Sch?tzen Sie Ihren PC mit McAfee und WEB.DE. 3 Monate kostenlos testen. http://www.pc-sicherheit.web.de/startseite/?mc=022220

16 years, 12 months

AIX 3.2 Installation Media - anyone got a spare set?

by glen.slick＠gmail.com

I rescued some 1990 vintage RS/6000 7012 & 7013 boxes which I don't know much about yet. It appears that AIX v3 is what originally would have been installed on these. Anyone got a spare set of AIX 3.2 installation media that I could use to get an OS loaded on these again, or know where I would have any luck finding this? A quick check of eBay turns up some V5 installation media for sale, but that would most likely choke on these old boxes and I don't see anyone currently listing old AIX versions. -Glen

16 years, 12 months

Classiccmpers near Dusseldorf?

by ethan.dicks＠gmail.com

Are there any list members in or around Dusseldorf or Wuppertal? It looks like the University is sending me there for a few days in August. I've spent plenty of time in Munich, but don't know much about other parts of Germany. Cheers, -ethan

16 years, 12 months

Interesting hardware and computer intellect

by jbmcb1＠gmail.com

The recent discussion on interesting system architectures triggered a memory I have of a documentary on TV somewhere (Discovery? TechTV? PBS?) on evolvable hardware. There was some intrigue in the episode, on investors accusing researchers of bad faith, or lying, or a scam. Hardware was built, I'm pretty sure it was the CAM-Brain, and it was used quite a bit before the company that built it went under (It may have been Genobyte along with ATR, but I remember the company being based out of England) Anyways, this definitely counts as "interesting" hardware. An FPGA based computer that optimizes it's own logic based on a given problem. The CAM-Brain was built, as was an FPGA engine built by HP, and another in Japan somewhere. Here are some links if anyone is interested: The CAM-Brain: http://trappist.elis.ugent.be/~heeckhau/CBM/ Hugo de Garis has an interesting website discussing weather we should build super-brains (Artliects) or not: http://www.iss.whu.edu.cn/degaris/ Adrian Thompson, one of the bigwigs in evolvable hardware design: http://www.cogs.susx.ac.uk/users/adrianth/ade.html

16 years, 12 months

Advice/Suggestions for repairing Apple III power supply

by ethan.dicks＠gmail.com

On 7/23/07, Richard Smith <richard.smith at mewgull.com> wrote: > >Hi all -- > > > >Picked up an Apple III this weekend in non-working condition, and I > >suspect the power supply is at fault. > > > >Symptoms are: On power up, a rapid clicking noise is emitted from > >the power supply (maybe 4Hz or so), and the power LED on the > >system's motherboard pulses at the same rate. > > It's an early switch-mode power supply and the ticking is the device > trying to start up, the control circuit says something is wrong, so > it shuts down. And cycles all over again. I concur. > Disconnect the PSU from the rest of the computer before you try anything else. Indeed, though you might get different behavior with no load whatsoever. This is where those 6V headlamps come in handy. > I would trouble-shoot by looking first at Q1 since that is the > switching transistor, and then maybe all the electrolytics on the +5V > and -5V rails since they are used to provide the reference signal for > the feedback circuit. It's all very simple (compared to modern > switchers). Agreed. One other thing to consider - I've seen this behavior in other machines when there was no problem whatsoever with the PSU - the problem was with the motherboard - a dead short, typically. If you test the PSU with no load or a dummy load, you might get the PSU to start up. If that happens, check the resistance of each voltage input of the motherboard to ground - resistances near 0 or 1 ohm would suggest a problem on that rail. I last saw this behavior when I attempted to use a modern ATX supply on a Blue&White Mac G3 - the PSU ticked and wouldn't start. Turns out that Apple recycled the pin for -5V as an additional ground. Clipping that pin solved the problem (the Mac doesn't need -5V) - it all started normally and runs fine. Stock ATX supply and stock G3 mobo results in ticking. Without further investigation, you can't easily tell, but it could be either the PSU not starting or it could be the protective circuit kicking in. You can do a lot with a VOM and some resistive loads. -ethan

16 years, 12 months

1966 Mag: Build NE-2 Neon Bulb Computer - scan available

by jam＠magic.com

> On Sunday 22 July 2007 19:40, davis wrote: > > I just read an recent article in eetimes that the target life of new > > ICs is 10 years. This is due to metal migration and other (i can't > > remember ) effects that sub-micron processes exhibit. I guess you > > should hang on to all the old gear you can get, because everything > > built today will be land-fill in 10 years. I too have that microwave, > > stainless on the outside for no apparent reason and a painted > > interior. The coating failed after a few years. > > "Target life-time" doesn't mean that every one of the chips will be dead > in 10 years. Realistically, at worst, 1/2 will be dead in 10 years, > and more likely than not it'll be somewhere more favorable on the bell > curve than that [an insignificant amount of dead chips until 10 years > out]. There's plenty of products that were produced 20+ years ago > which had worse "target life" (though not all of it had anything to do > with design). Yes, it's much further out on the normal curve. Chip makers have a strong incentive to make chips have long lifetimes. Nobody is going to buy huge volumes of chips that will all die soon. Complicated chips in modern geometries often take many $1M's and often $10M's to develop when you consider the NRE (a few $M's), the tools, and the number of person-years that go into them. If you build chips that die soon, you won't have any customers and that makes it kind of hard to recoup all of those $M's. You really want the product to become obsolete for some other reason than because the chips start dying. If you were creating a mass-market product, would you want to take a $1B write-off on earnings when the world discovered your stuff dies before it's "natural" obsolescence cycle? The general practice is to take the desired lifetime (often 10 years for the server type of chips that I usually build), worst case average temperature, worst case voltage, maximum frequency, pessimistic estimate of how often each signal inside the chip switches, and worst case process variation. A program then applies a formula to each of the structures in the chip design to see if each meets the lifetime expectation with some probability, well over 99%. The models used by these programs take more and more effects into account with each generation. Foundry's work very hard to have good models and work very hard to understand what structures will age poorly and provide design rules to avoid those. Sometimes they mess up and they spend $100M's or more to fix it because their reputation is valuable. For server type applications, the design teams work very hard to be sure that all of the estimates are *not* optimistic. More often, the estimates are fairly pessimistic. The reason is that the probability needs to be really high if you are putting a lot of chips into a box and want the box itself to have a lifetime of 10 years; if a box has 100 chips with only 99% probability of 10 year lifetime, then the contribution >from the chips alone would mean that only 37% of the boxes last for 10 years. Bringing this somewhat back on topic ... one of the worst factors in the equation is the average operating temperature. The lifetime falls exponentially with the temperature. If you can get your chips 10 degrees cooler, you will greatly extend their life; make sure boxes have good fans and that the fans are working well. I don't know what fudge factors and design life were used for commercial chips from the '70s, but no matter what the target was, keep it cool! James Markevitch

16 years, 12 months

← Newer
1
...
8
9
10
11
12
13
14
...
33
Older →

Jump to page:

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb July 2007