test-drb February 2009

test-drb@ccmp.vtda.org

196 participants
309 discussions

by aek＠bitsavers.org

Almost nothing was out there for the low cost ICE's that Microtek built, so I scanned and took some pictures of the bits that I have. Additional personality docs (esp for the MICE-II 6502 and 6809) would be nice to find. Still need to take some pics of the original 6502 MICE that I have. http://bitsavers.org/pdf/microtek/mice

16 years, 1 month

PDP-11 power requirements

by tiggerlasv＠aim.com

I can't speak towards the older, larger Unibus models, such as the 11/45, 11/55, 11/60, and 11/70. However, these models generally had a standard 115volt line cord: 11/02 11/03 11/23 11/23+ 11/24 11/34 11/34a 11/44 11/53 11/73 11/83 11/84 11/93 11/94 (Sorry in advance, if I left anyone's model off the list.) ;-) If it's in a rack, it MAY have a power distribution module at the base, with a 20-amp or 30-amp power cord, but in most (if not all) cases, the individual chassis inside the rack will have standard 115volt line cords that plug into it. T

16 years, 1 month

S-100 backplane board spacing

by aek＠bitsavers.org

> does anybody have a handle on where I > could obtain 5 S100 edge connector sockets? You also need to specify the spacing of the circuit and component side pins on the connector for your backplane. There are at least two different spacings that were used. Most were the wider style, early MITS backplanes had closer spacing.

16 years, 1 month

S-100 backplane board spacing

by ajp166＠bellatlantic.net

> >Subject: S-100 backplane board spacing > From: "Andrew Lynch" <lynchaj at yahoo.com> > Date: Thu, 05 Feb 2009 22:32:10 -0500 > To: <cctalk at classiccmp.org> > >Hi! Is there any sort of a standard for S-100 backplane spacing? > >I measured a couple of backplanes I have (a VG and another one) and they >both measured .375" (3/8") gap between the connectors. That seems rather >closely spaced to me if the boards are 3/4" apart if the connectors are 3/8" >wide themselves. > >What would be the minimum useful gap between S-100 connectors for a small >hobbyist S-100 backplane? I presume 3/8" gap is not enough if you want to >accept prototype boards with wire wrap sockets and maintain some clearance. There are two considerations, airflow and bus length. Wider gap helps airflow to a point then wider doesnt help as much. Wider spacing makes the bus longer for a give number of connectors and longer has more problems with reflections(ringing) and other transmission line behavours. Longer may also impact power distribution as well. Last items is the height of boards limits how close or forces skipping slots. Some fo the taller boards in my collection suggest greater than 0.75" center to center would barely be adaquate because of tall heatsinks contacking the next board. Look at the better backplanes, Compupro would be one. Also the later boards (more modern) were dense enough that only a few slots are required. I have at least two machines that are: Zpu-B z80 cpu 64K ram (ram 16, 17 or 22) Interfacer (multi serial plus parallel) DISK1A FDC DISK3 HDC Systemm Support Thats only 6 boards and the smallest backplane I have is 8 slots. It's as loaded a system as most or more so. The limiting factor for the box is fans, power supply and mountings for the disks. Older antiques like an altair filled with then current board may have: CPU 8080or later Z80 Ram boards anhywhere from 4k per to 16K per (as many as 8 for 64K) Some form of rom boot card possible a dual board FDC (altair disk was a two card set) multiple IO baord for serial possible multiple boards for one or more printers or other parallel devices. And cooling issues. Hope that helps with some history. I'd say 6-8 slots spaced 1" and also on the board terminator. Allison > >Any constructive thoughts on the subject much appreciated. > >Thanks and have a nice day! > >Andrew Lynch

16 years, 1 month

Simulation vs breadboarding (was Replacing failed powersupplies on qbus PDP-11s)

by aek＠bitsavers.org

> Aquarius project? A mostly accurate description can be found in http://lowendmac.com/orchard/06/john-sculley-years-apple.html

16 years, 1 month

Need a copy of an IRE article

by evan＠snarc.net

Can anyone assist me in getting a copy (pdf preferred) of this article: Proceedings of the IRE, Oct. 1953 (Vol. 41, Issue 10), pages 1388-1392. The article is called. "The Design of Logical OR-AND-OR Pyramids for Digital Computers" ... thanks! - Evan

16 years, 1 month

Ideas for disposing of entire collection

by robert.stek＠gmail.com

Thanks to those here and on comp.os.cpm who have responded publically and privately with some ideas I had not considered before. I know there is at least one ebay selling service in Tucson, a solution I hadn't thought of. I wouldn't mind spending the time describing items correctly if that's how I go. I would be hoping that they have the space to take it so I could get it organized for them. I will also get in touch with Sellam. I have been to a few users group meetings here in Tucson but have never met anyone suffering >from the classiccmp disease - perhaps a few weeks worth of notices on Craig's List might scare one or two out of the woodwork. To those who have responded with wish-lists: the biggest problem in my current situation is that too many boxes are labeled "Old computer stuff" or even those that are labeled '8" disks' are in X different boxes in Y different places, usually with boxes in front and on top of them! If I could easily retrieve specific items I would rather they go to people on the lists who appreciate them. Alas, when I packed them away I fantasized that I would have sufficient room to organize everything properly - the reality is that I don't. If I go through an ebay service I might be able to pull some stuff that people have mentioned. I was surprised (thrilled?) to hear that at least one person thought $15-$25k was a reasonable ebay estimate. Frankly that about twice what I would estimate (at least in today's economy!). Maybe I should just sit on it all for the next 2-3 years and wait until one of the next Web 3.0 millionaires wants a legacy collection! Jim Battle, you and Barry Watzman are the only 2 people I know with working Helios systems. If I find those Helios disks I lent you a few years ago, you two guys can split them if you want them. Bob Stek (former) Saver of Lost Sols

16 years, 1 month

ISO older PROMICE manuals

by aek＠bitsavers.org

Does anyone have copies of the various revisions of the Grammar Engine PROMICE? I have a manual for a really early version of the device, and have a few of them of various vintages made in the 90's which neither match my manual, or the current versions.

16 years, 1 month

Replacing failed powersupplies on qbus PDP-11s

by toby＠coreware.co.uk

Hi, I have a couple of uPDP-11 boxes (BA23) with failed power supplies. Being no expert on repairing switch mode power supplies (and to be frank slighly scared of trying), is there any reason why I shouldn't adapt a ATX power supply from a PC to provide the required voltages? Most ATX power supplies offer pretty meaty 5V and 12V feeds plus a fairly small -12V (~0.3A) feed. Will I need to generate a LTC/BEVENT L signal if I go down this route? Finally, does anyone know of any good guides on repairing switch modes? Whilst not keen, I guess I should bite the bullet (hopefully not literally) and learn how to repair them. Thanks, Toby -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.

16 years, 1 month

Simulation vs breadboarding (was Replacing failed powersupplies on qbus PDP-11s)

by aek＠bitsavers.org

> Until the boss sees that you screwed around in the lab for an hour or > two getting all the parts and building the test circuit I doubt any company newer than 10 years old even has lab stock any more to breadboard something with. I'd end up going to Haltek or Halted for parts, because Apple killed off their parts stock room when the hardware group was moving from Valley Green to Infinite Loop. One day I went over to it and it was empty. They had dumped the whole thing into recycling because none of the hardware engineers used any of it anymore.

16 years, 1 month

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test-drb February 2009