test-drb April 2008

test-drb@ccmp.vtda.org

196 participants
307 discussions

are there any 68000 multi-cpu systems out there?

by trag＠io.com

>Date: Fri, 18 Apr 2008 19:12:41 -0400 >From: Ray Arachelian <ray at arachelian.com> >Subject: are there any 68000 multi-cpu systems out there? >Just out of curiosity, were there any machines out there that were built >from multiple MC68000's CPU's? There was the MassComp from Massachusets Computer, IIRC. However, it wasn't exactly a multi-CPU system. It used one 68000 for processing and another one to handle the very fancy (at the time) color graphics system. It ran some flavor of Unix. I learned (taught myself) C on that machine. We had several of them at NASA JSC around 1984 - 1985. Jeff Walther

16 years, 8 months

About Intel386 Family System Builder User's Guide

by huxuelei630＠gmail.com

Dear sir, I am sorry to bother at this time. I have read about your arctile at http://www.classiccmp.org. I wonder whether you have the document Intel386 Family System Builder User's Guide? If you have, could you please send me a copy of it? I have been looking for the document for a long time. Thanks. Huxuelei

16 years, 8 months

Beginner's capacitor question

by trixter＠oldskool.org

I have a need to record the output of a (5150) speaker. Although I thought that I could just alligator-clip a positive lead to one speaker terminal and the negative to the case/ground, the output was decidedly "buzzy" (I assumed it was too "hot" and overmodulating). I routed it into a mixer and turned it down (speaker is 5v, not sure what line input is) but it still didn't sound right. I found some old directions on hooking up a PC speaker to a line input, and was confused by the use of a capacitor -- I would have thought that a resistor would have been more appropriate, to limit the signal perhaps? In any case, here are the instructions, followed by my question: Parts required: - 6' to 12' shielded cable with RCA plug (male) on one end - Two alligator clips - One 4.7 uf capacitor 1. Connect one alligator clip to the shielded portion of the cable. 2. Connect the (-) minus side of the capacitor to the center conductor of the cable and then connect the (+) side of the capacitor to the second alligator clip. 3. Attach the clip with the capacitor to one of the wires going to your computer's speaker. Attach the other clip to the metal case (ground) somewhere (such as a screw or bolt connection). 4. Connect the RCA plug to the auxiliary input on your stereo system or boom box. While I have read the wikipedia entry on capacitors, I'm missing something obvious. My question: Why the 4.7uf capacitor? Does it serve to limit the signal? Reduce it's voltage? (or increase it?) Filter the signal in some way? -- Jim Leonard (trixter at oldskool.org) 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/

16 years, 8 months

Help with ICL power supply fault (Farnell SMPS) - now working

by john_a_s2004＠hotmail.com

Hi again, Thanks for the tis on SMPS faults, I have now got it up and running. The first fault was a failed Y suppresion capacitor on the input - this had split open with a 'pop', easy to spot and replace. Then the PSU gave 1.1V on its 5V output, this was because the output was not regulated and went over volts, which triggered an SCR on the 12V rail. I removed the SCR and thought it was faulty, but the replacement had exactly the same resistance (80 ohm from gate to cathode in either polarity) so I fitted it anyway. I checked the voltage at the opto isolator and saw it vary as a changing voltage was applied to the 5V output, so this looked good. I tried drawing a circuit diagram based on the layout, but found this very difficult. However, I found two bad soldering joints when tracing the circuit. These were both at points when a trace on top of the PCB met a component then carried on underneath the PCB - ie the circuit relied on the solder forming a joint both under and on top of the PCB. I then applied varying DC to the input (up to 110V, this is a 230V supply). At around 80V, the board made a loud whistling noise, and the 5V and 12V outputs came up. However, as the input voltage was varied the output varied in step. I then checked the quad comparator chip (CA338, equivalent to LM338) and decided it was faulty. This was soldered in so replacing it with a socket was a pain. Anyway, with a new chip fitted the PSU came up fine. I still don't understand the whole circuit, there were around 5 transistors in an ossicaltor circuit which I couldn't get to grips with. I found the following sites helpful: http://www.sencore.com/custsup/techtips.htm - I used the 'dynamic testing' approach, looking at the SU in blocks. http://www.datasheetarchive.com/ Once back in the machine everything seemed normal again. I dnt seem to have a boot disk, but that is another story! Thanks, John _________________________________________________________________ Get Hotmail on your mobile. Text MSN to 63463 now! http://mobile.uk.msn.com/pc/mail.aspx

16 years, 8 months

Paratronics Logic Analyzer

by jamesmavery＠mchsi.com

I need a copy of the paratronics PI-540 logic analyzer

16 years, 8 months

IBM-9000 Computer System

by billdeg＠degnanco.com

> >I'm trying to find one of these systems and so far I am having absolutely no >luck at all. >Aside from some info and a few photos on the Old-Computers.com website I >can't find anything else relavent to this system and so far I can't find >anyone who has even heard of the things let alone seen one. Has anyone here >ever seen or used one and does anyone here even own one? I want to use one >to replace my unreliable VT510 serial terminal as well as try out the >IEEE-488 port. > >Oh yeah, here is a link to that info on the system. >http://www.old-computers.com/museum/computer.asp?st=1 ><http://www.old-computers.com/museum/computer.asp?st=1&c=623> &c=623 > > >John. > John, I too have been looking for one of these. There is a detailed article about the 9000's in the special issue of Byte, BYTE Guide to the IBM PC, fall 1984. Page 219 there is an article titled "Number Crunching on IBM's New S9000. "IBM joins with MIT's National Magnet Lab to develop spectrometers for imaging systems" by David J States. I have this as one of my "10 Most Collectible Micro Sleepers" ... http://vintagecomputer.net/browse_thread_record.cfm?id=94&tid=1 ...which was my response to PC World's article titled "The Most Collectible PCs of All Time" If you find two, let me know! Bill

16 years, 8 months

IBM 3852 Color Printers

by mbbrutman-cctalk＠brutman.com

I have two of these - a Model 1 and a Model 2. I never used them - it's an interesting project, but I don't have the ability to clean and repair something as delicate as an inkjet nozzle. Does anybody have any interest in these? If so, email me off list. I'm in Rochester, MN (55902) - shipping will be pricey, as these units are heavy. Mike

16 years, 8 months

Monitors to go

by kenziem＠sympatico.ca

As part of Earth Day celebrations I have a chance to recycle stuff without the normal charges for monitors Sun M19P114 Sun CD1 version C Sun GDM 1604-15 HP 98754A Digital VRT19-ha Nec Multisync Jc1401P3A Unisys - was off of an ICON a bunch of other 12-14" PC/Apple monitors If anyone wants one of these first, let me know before Wednesday evening. They are located in Ottawa, but a few list members do make trips this way. Mike

16 years, 8 months

are there any 68000 multi-cpu systems out there?

by hardware＠ees1s0.engr.ccny.cuny.edu

My undergrad school had a Stardent with four 68k processors. It ran some sort of Unix. They used it for simulating nonlinear optics. I took posession of the manual before they discarded the whole system. Property accounting bureaucracy prevented me from keeping system hardware. -kurt

16 years, 8 months

Early spring cleaning...

by derschjo＠msu.edu

Hey all -- I'm trying to free up some space so I have some stuff I'm looking to give away. Local pickup in the Seattle area only, please. Computers: - Commodore PET 8032. Works, someone managed to do a bit of damage to the PCB when replacing a RAM chip or two. Seems to work fine. - Miscellaneous 386 & 486 laptops. Most with 4/8mb ram & hard disks, some missing AC adapters. If you're interested, I can provide more detail - HP 9000/236. W/monitor. Worked last time I powered it up. Missing the "S" key on the keyboard, otherwise in good shape. Terminals: - 2 TRS-80 DT-1 terminals. With dust covers! Powered up the last time I tried them over a year ago. - Wang 2256-C terminal. Heavy. Not sure it's an actual dumb terminal, I get the impression it goes with a word-processing system. As it is it powers up, displays a green screen, and beeps once. (CRT needs a tune-up) Monitors: - Gateway SVGA, 15". Trinitron, works well. - Mitsubishi Diamond Scan something-or-other. CGA/EGA, composite, TTL, etc. 12 or 13". Works, a bit scuffed. Misc: - IBM Microchannel Token Ring cards. Probably work, I don't have any token ring hardware to test with. Let me know if anything strikes your interest... Thanks, Josh

16 years, 8 months

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test-drb April 2008