test-drb May 2008

test-drb@ccmp.vtda.org

199 participants
350 discussions

by aek＠bitsavers.org

> This is not relevant to this particular rescue, but I know nothing > about these systems and am curious. What type of OS and app software > do machines like this run? 990's are 16 bit computers heavily influenced by the architecture of the pdp-11. The main difference is the working registers were kept in memory, allowing very fast context switches, at the expense of register access performance. Later machines cached the register sets. There was a small single-user floppy disk based os (for the 990/4 based on the TMS9900), but the main OS was DX-10, which was replaced by DNOS on the 990/12 series. Their primary use was in small buisiness, they had COBOL, FORTRAN, BASIC, and things like rje, data base and forms management packages, and networking. It seems they were widely used in inventory and parts management systems. The history of the 990 says the system was originally developed as part of a hotel management system. dave pitt's site (as well as bitsavers) are good sources of information http://www.cozx.com/~dpitts/ti990.html

15 years, 11 months

Transformer repairs

by dr.emiel＠xs4all.nl

Ade, I think you mean the small transformer with 6 wires attached, this transformer has 2 * 9VAC outputs and one AC-line input (230 or 110V depends on region) This transformer is the supply for the regulator IC's in the PSU the regulators are places on two small PCB's, on the large PCB there is a rectifier (Greatz) witch you have to check. If thats alright you have a reasonable change the PSU works after replacing the transformer with a similar type 2 * 9VAC 3 to 5VA. Rik -----Oorspronkelijk bericht----- Van: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org] Namens Ade Vickers Verzonden: woensdag 28 mei 2008 18:38 Aan: 'General Discussion: On-Topic and Off-Topic Posts' Onderwerp: Transformer repairs I was messing around with my SX-64 (which is on ePay as a working unit) yesterday, having located some software & a joystick for it. I was going to take a few photos of the new bits, etc.; for adding to the listing. Then: *sharp snap/crack noise*, lights go out. Aaaargh! OK, first things first: There was no burning smell, and no (visible) magic smoke released. The fuse wire in the glass fuse has been vapourised; the mains fuse survived. I replaced the fuse, which has not since blown, but the PSU is deader than a dead thing that's been dead for a week. Some careful poking around with the multimeter (before the multimeter went bang - ffs, I must have an anti-midas touch this week), then the oscilliscope, reveals that a secondary transformer on the PSU has failed. I presume it went dead short, then burnt itself + the fuse out simultaneously; hence the reason the replacement fuse hasn't blown. So, what I need to do now is replace the transformer, or get it repaired somehow (ideally before Sunday, when the ePay auction runs out - or, to definitely know it is unfixable in that timescale & thus cancel the auction). What I DO have, which might make a repair feasible, is a second SX-64; the only difference is, this one has a US (117v) PSU. Obviously, the primary transformer windings are going to be different, but is it possible/likely that the secondary transformer will be the same? Going by the part nos. I'm not terribly hopeful: UK Part no: TDK 68-0409 B8326A US Part No: TDK 68-0407 B8309A A quick google on any of those numbers reveals nothing... I don't have the means to create 117v 60hz power, so I can't test that way - and even if I could, it turns out that the US PSU has taken a wallop at some point, breaking the circuit board. :( Hey ho... any help gratefully received. TIA! Best Regards, Ade. No virus found in this outgoing message. Checked by AVG. Version: 7.5.524 / Virus Database: 269.24.1/1469 - Release Date: 27/05/2008 13:25

15 years, 11 months

Introduction

by roger.holmes＠microspot.co.uk

On 30 May, 2008, at 18:00, cctalk-request at classiccmp.org wrote: > > Message: 9 > Date: Fri, 30 May 2008 17:11:02 +0200 > From: Oliver Lehmann <lehmann at ans-netz.de> > Subject: Introduction > To: Classic Computers Mailing List <cctalk at classiccmp.org> Welcome Oliver. > The system runs a Z8001 with 3 MMUs and Z80-peripherial ICs (PIO, > SIO...) > It also has 2 SIOs for 4 terminal connections, and one PIO to > connect the > WDC. The system also has two furhter PIO chips to establish a > connection > to the 8Bit system. The system runs with up to 4MB of DRAM but it > might > run with more RAM with self-made RAM modules. Three MMUs seems a bit weird. I last programmed a Z8001 in 1979 so maybe things have changed between then and when your machine was built. If I remember correctly, the Z8010 MMU mapped 64 of the 128 segments, you could have one MMU and address 64 chunks of up to 64k in the 16MB address range. With two MMUs you could access all 128 chunks. Are the MMUs set up for different processes, or are they divided into instruction and data accesses or some other way? The system I worked on would have eventually had 12 Z8001s each with one MMU and 128K of local RAM plus the CPU were grouped into modules of three and had about 3MB of RAM in the module and each module could also access the other 3 module's RAM, but with more wait states. Each Z8001 was responsible for managing a wide microprogrammed bit slice processor for doing heavy mathematics, though the details might still be secret even though the project was cancelled in the mid eighties, several years after I left the company. I got involved quite early, the first draft of the Z8001 instruction set manual which I was given included a memory to memory transfer instruction, but that was dropped before they issued the first sample chips about a year later. A bit of a blow as we had started writing a Coral 66 compiler for it by then. When I retire I might get around to getting myself a Z8001 system if there's any still around by then. I am kept busy at work programming Apple Macs and at home restoring a 1962 mainframe computer (ICT 1301) and restoring/maintaining my old cars (2 Daimlers, 2 Rovers, a Land Rover, a Jaguar and a BMW). I think you would have to be lucky to get your C code to use exactly the same registers as the original object code. Are you sure it was originally C or could it have been assembly code?

15 years, 11 months

WOPR sells on eBay

by sellam＠vintagetech.com

This is actually a replica of the original WOPR that was commissioned for an AT&T commercial a couple years back. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=220237845125 -- Sellam Ismail Vintage Computer Festival ------------------------------------------------------------------------------ International Man of Intrigue and Danger http://www.vintage.org [ Old computing resources for business || Buy/Sell/Trade Vintage Computers ] [ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]

15 years, 11 months

PET 2001-8 progress...

by derschjo＠msu.edu

So I've got my "hacked-up" PET powering up after redoing a bit of wiring on the power supply. I replaced a couple of obviously bad 74LS157's in the video generator section (legs were corroded and some had fallen off/cracked) and reflowed a couple of suspicious looking joints. The machine now powers up, the display is bright and crisp but I just get garbage characters on the display. Using my logic probe I've verified that the CPU is running, voltages appear nominal (4.9V at the CPU & RAM). The CPU seems to be running something, in that about 1-2 seconds after power up a few characters on the screen will change (not where you'd expect the COMMODORE BASIC banner to be printed, but always in the same places). Typing on the keyboard produces no effect. I've reduced the board to 4K of 2114s and tried swapping around the 2114s used for the display, but the only effect this has is to change the pattern of garbage characters displayed (interestingly (at least to me) each RAM chip produces a different pattern, which is reproducible). If I run without any video RAM installed, I just get a checkerboard pattern onscreen, which would make sense since character FF is the checkerboard tile. Unfortunately I have no idea if any of the 2114s I have are good or not, though I'd wager that they can't ALL be bad. I don't have any other machines that use them and I don't have any spares. Any suggestions on logical places to start looking from here? Thanks, Josh

15 years, 11 months

Transformer repairs

by cclist＠sydex.com

> Date: Sat, 31 May 2008 11:41:15 -0400 (EDT) > From: der Mouse > It is probably possible to build a current limiter that provides > immediate visual feedback. I challenge you, or anyone for that matter, > to come up with such a design that is as cheap, easy, simple, and > foolproof as an incandescent bulb. (Well, not cheap once the ban hits, > which is the problem.) How's this? Grab a glass jar, fill with water and a salt of your choice, say, bicarbonate of soda, drop two electrodes into it (stainless steel or carbon is good; aluminum will tend to polarize after awhile and form a leaky rectifier). Apply current and watch for bubbles and/or steam. Vary resistance by varying the distance between electrodes. Or use a dill pickle instead if you like glowing pyrotechnics. We will always have appliances with heating elements floating around that can be pressed into use, particularly where higher-power loads are concerned. What I don't like about incandescents used as a load-limiter is the very low cold resistance. I'd much rather have a "soft" start--but then carbon-filament incandescents haven't been easy to find for the last 80 years or so. Cheers, Chuck

15 years, 11 months

Big Board I: micro cornucopia & user disk

by elazzerini＠interfree.it

Hi at all, i'm looking for all articles and software for the big board I. ( <http://en.wikipedia.org/wiki/Ferguson_Big_Board> http://en.wikipedia.org/wiki/Ferguson_Big_Board) There was a magazine called Micro Cornucopia ( <http://en.wikipedia.org/wiki/Micro_Cornucopia> http://en.wikipedia.org/wiki/Micro_Cornucopia) Some issues are scannered here below: <http://www.aceware.iinet.net.au/acms/BooksByManufacturerList.asp?lngManufac turerId=980&strManufacturerDescription=Micro+Cornucopia> http://www.aceware.iinet.net.au/acms/BooksByManufacturerList.asp?lngManufact urerId=980&strManufacturerDescription=Micro+Cornucopia The issues i'm looking for are from the 1st to the 22th. There was also an DRI Archive of the Big Board user disk. I'm looking from the #1 to the #20. They contain sw utilities bios lists and all about this OLD SBC. I thanks to all would be help to rebuild all info around this board. Enrico - Pisa - Italy

15 years, 11 months

video game cartridges

by dgriffi＠cs.csubak.edu

I know that some of you here have an interest in vintage video games. How many of you would be interested in getting together a pool to make new Atari 2600 and Vectrex cartridge cases? -- 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

Thanks! REXT Diagnostic ROM and POSTcard

by lynchaj＠yahoo.com

Andrew Lynch wrote: > Long story short, I replaced a 74LS245 and a faulty DRAM chip and now the > board boots fine. The DRAM I could probably figure out myself, but how did you determine the 74LS245 was at fault? (I, too, have a 5150 that won't boot) -- Jim Leonard (trixter at oldskool.org <http://www.classiccmp.org/mailman/listinfo/cctalk> ) http://www.oldskool.org/ Help our electronic games project: http://www.mobygames.com/ Or check out some trippy MindCandy at http://www.mindcandydvd.com/ A child borne of the home computer wars: http://trixter.wordpress.com/ -----REPLY----- Hi, The old fashioned way; I used an oscilloscope to compare the inputs and outputs of the bus transceiver. One of the buffers was dead and all of the outputs on one side looked "funny" so I desoldered it and replaced it with a new one. Of course, the IBM PC/XT motherboards have few sockets so desoldering and replacing the chip was awful. I tried to nicely desolder it but ended up destroying the chip and cutting it out. One thing I really like about VG, NorthStar, Kaypro, and Heath is almost their entire motherboards are socketed. Yes, I know direct soldered chips are technically more reliable but they are a PITA to replace when they do fail. Thanks and have a nice day! Andrew Lynch

15 years, 11 months

Old style DEC 5-1/4" "pop panel" needed (will trade for 10 1/2")

by bob＠jfcl.com

I need a DEC, old style, "pop panel" blank rack panel that's 5 1/4" high. I'd be happy to trade for a 10 1/2" pop panel if that helps anybody (heck, I'll trade for two - I've got several of the 10 1/2 panels). Thanks, Bob Armstrong

15 years, 11 months

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test-drb May 2008