test-drb April 2008

test-drb@ccmp.vtda.org

196 participants
307 discussions

IS32 Optic RAM Datasheet and Steve Ciarcia's Micro D-CAM Artical

by jwallis＠fbiacademy.edu

Mr. Dunfield, In a 2004 posting you indicated that you had a copy of the Micron Technology IS32 OpticRAM data sheet. Have you ever scanned the document? Would it be possible to obtain a copy? Your assistance would be appreciated. Jane Wallis

16 years, 1 month

Help with ICL power supply fault (Farnell SMPS)

by pcoghlan+cctech＠vms.eurokom.ie

> >One way to achieve isolation is to get a couple of filament transformers that >are of similar voltage ratings and use them both, tying both low-voltage >windings together and using one primary as the output. I'd think that they >wouldn't need to be particularly hefty if you're not going to load the supply >much. > Another approach I keep meaning to try out, also for small loads, is a bathroom shaver outlet isolating transformer. Many, like the one in my junk box, also have the advantage of providing a choice of output voltages so that equipment designed for the other side of the Atlantic only can also be tested. (I last thought of this approach just after I blew the input fuse in a small SMPSU after somehow managing to confuse myself about which were the input rectifiers and which were the output rectifiers. But it was too late then so I didn't bother...) One thing that puts me off though is that I vaguely remember reading a report from someone who had a SMPSU that behaved even more bizarrely than these things usually do when it was powered through a less than ideal isolating transformer. Regards, Peter.

16 years, 1 month

Fwd: [comp.sys.sgi.hardwar...] Power Challenge XL available

by Arno_1983＠gmx.de

Richard <legalize at xmission.com> wrote: > This message has been forwarded from Usenet. To reply to the > original author, use the email address from the forwarded message. > > Date: Wed, 9 Apr 2008 00:39:44 -0700 (PDT) > Groups: comp.sys.sgi.hardware,comp.sys.sgi.admin > From: "fischerc at itam.cas.cz" <fischerc at itam.cas.cz> > Org: http://groups.google.com > Subject: Power Challenge XL available > ======== > Hi everybody > We have a rather big piece of HW: SGI Power Challenge XL (6 x R8000 at 75 > MHz, 1G ram, a few 2-4Gb SCSI discs) available here in Prague (CZ, > EU). > The computer was cleanly shut down on May 5, 2004 and since that time > was not touched. We intend to scrap it now. If anybody wants to have > some spare parts or even the complete beast, let me know within 1-2 > months. > I regret to say, that this was the last SGI machine we have here. > > Anyway, I would like to express my thanks to the SGI admin comunity > for all the help I've received in past years. > > Sincerely yours, > Cyril F. Hey, Prague - we have relatives there! Unfortunately the machine seems to be a bit too big to fit into a Volkswagen Golf Variant, else we could have offered to rescue it on our next visit there. If somebody feels like it's road trip time for this baby and an appointment can be made, I'm volunteering as a loading and handling assistant! There are stacks of testimonials from satisfied customers ;-) So long, Arno -- Arno Kletzander Student Assistant // Studentische Hilfskraft Informatik Sammlung Erlangen www.iser.uni-erlangen.de Psst! Geheimtipp: Online Games kostenlos spielen bei den GMX Free Games! http://games.entertainment.gmx.net/de/entertainment/games/free

16 years, 1 month

DM8552

by aek＠bitsavers.org

http://bitsavers.org/pdf/national/_dataSheets/DM8552.pdf

16 years, 1 month

DM8552

by aek＠bitsavers.org

> Someone on the list could go to Halted, get a copy, and scan it for him. I scanned the entire data book last week. I'll see about getting it on line.

16 years, 1 month

Compaq Portable 1 for sale - between Boise and San Diego

by tosteve＠yahoo.com

Contact Joe if interested: lather222 at hotmail.com Original Compaq Portable I for sale for $??.??. It boots to green cursor, but no floppies available to verify. Joe is in Boise Idaho, but will be DRIVING to San Diego and Los Angeles area via Las Vegas in early June. Price unknown, but around $50 probably acceptable. Contact him if interested: lather222 at hotmail.com __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

16 years, 1 month

Help with ICL power supply fault (Farnell SMPS)

by john_a_s2004＠hotmail.com

Hi, I've started to setch the output circuitry, not 100% accutarely as my meter shows all the transformer windings as 0 ohm, so I have some points that measure 0 ohm to ground which may be ground or maybe a transformer output. Thanks Tony for your reply, quote below. Tony wrote: >John wrote> >> I have an ICL PC2 CP/M box (like this: >> http://www.old-computers.com/museum/computer.asp?c=752) which has a >> faulty PSU, I am hoping someone here can advise me. >> >> The PSU is a Farnell N100/F4190 SMPS, looks like a high quality unit >> with nice screw terminals for mains in and DC out. >> > When fired up with 240V AC and a dummy load the output voltages are: >> >> 12V output=1.1V >> 5V output=2.3V >> -12V output=-5.9V > >The first thing that 'bothers' me is that the 12V output is lower than >the 5V one. If this was a simple regulation fault, I'd expect all outputs >to track. > >Do you know which output the crowbar operates on (not which one triggers >it, but which one it shorts out?). Now I have some of the output circuit, I have found their is an SCR (2N6400) connected as follows: Anode - to +12V output Cathode - to ground Gate - to a resistor divider, which inturn is connected via a diode (assumed to be a zenner) to the +5V output. With the power off I have tried applying +5V to the +12V output, and this drew 250mA - ie around 20 ohm. most of this current turned out to be going through the SCR, as when I removed the SCR the current reduced to around 20mA. I think the SCR has been damaged, it is showing 80ohm between gate and cathode with the meter either way round (I think this should be a diode!). I guess the SCR must have taken the brut of the 80W or so of excess power taken by the PSU when I was testing it earlier. I'll buy a couple of replacements. > It's not uncommon for that to be >something other than the main output (simply becuase it's easier to pull >down), it's possible there's a crowbar thryistor on the 12V output, and >that that's firing. Exactly right - thanks for the tip. >I assume this thing doesn't have external sense inoputs for the main >output, or if it dows you've conencted them to said output. No sense inputs. >I think it's reasonable to asusme the chopper is working (otherwise you'd >get no outputs at all). Does it seem to be running continuously, or do >you get the 'tweet tweet tweet' of a PSU that's starting, detecting a >fault, shutting down, and repearing? > >Are tyhe otuptus steady at those votlages? I find an analogue meter best >for this, you can see the needle twitch if the PSU is starting and >shutting down. When I tested it earlier I applied power for around 5 seconds at a time, outut voltages were fairly stable. Next thing I'll look at is the feedback circuit from the +5V output via some resistors and what might be a FET into an opto-isolator to a circuit on the hot side involving a compartor, transistors, resistors and diodes. This looks fairly complicated (to me, probably a piece of cake for Tony!). Pity there isn't a nice IC controller like on the HP-85 PSU :-) Regards, John _________________________________________________________________ Get Hotmail on your mobile. Text MSN to 63463 now! http://mobile.uk.msn.com/pc/mail.aspx

16 years, 1 month

Seeking Xceed Color30 card

by trag＠io.com

> Date: Thu, 10 Apr 2008 10:16:50 -0400 > From: "Curtis H. Wilbar Jr." <rescue at hawkmountain.net> > David Griffith wrote: >> I'm trying to find a Micron Xceed Color30 card and Greyscale30 card for >> a >> Mac SE/30. > If anyone finds a stash of these... count me in :-) Heh. Typically, $300 - $500 on the rare occasions when they do show up on Ebay. I want one too...but not that much. I don't remember the exact URL, but google on Gamba SE/30 to get to a page with much discussion about this card. There are also a number of threads about it in the forums at 68kmla.net (68K Macintosh Liberation Army; rescuers of old, abandoned and unwanted 68K based Macintoshes). Some other discussion at applefritter.com's forums. The book the poster on the other related thread is probably thinking about is Larry Pina's "Macintosh Repair and Upgrade Secrets", which Tony probably disapproves of. :-) Pina discusses and recommends replacement of components based on the items which, in his experience, most often lead to certain symptoms. He does not discuss doing an actual probe and diagnosis to determine the failed component, which is why I good naturedly refer to Tony's disapproval. There are a couple of later variants on the above book, such as "Macintosh II Repair and Upgrade Secrets", "Mac Classic and SE: Repair and Upgrade Secrets", etc. These sometimes go for ridiculous sums on Ebay as well, but are often available at Amazon or other used book sites for very reasonable prices. At the moment "The Dead Mac Scrolls" are starting at over $100 on Amazon, but if the past is a guide, it will show up for under $20 if you wait around a while. Jeff Walther

16 years, 1 month

RL01/02 vs. RK06/07 terminators?

by mcguire＠neurotica.com

My dusty memory tells me that RL01/02 terminators are different >from RK06/07 terminators. Can anyone here confirm? Thanks, -Dave -- Dave McGuire Port Charlotte, FL

16 years, 1 month

HP Portable Vectra CS Model 20

by charlene＠dontmissyourlife.com

Via Google, I just found a two-year-old post of yours (http://www.classiccmp.org/pipermail/cctalk/2005-December/208439.html), which was in response to a four-years'-previous post about an HP Portable Vectra. You said you collect them. Well, I just unearthed my old one from the back of a closet. Interested in buying it? I see one listed on e-Bay for $499.99 OBO. I'm certainly not looking for that much! Charlene

16 years, 1 month

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test-drb April 2008