test-drb December 1999

test-drb@ccmp.vtda.org

186 participants
742 discussions

by edick＠idcomm.com

SRAM boards (that is what these are, isn't it?) are usually simple enough to troubleshoot that you can get by with just a 'scope and an hour or so of time, depending on how inclined you are to work on the hardware. Each RAM device will have a write strobe, a select strobe, (maybe a separate enable as well) and some data inputs and outputs. Because it's a 16K board, I assume you have 4kx1 or 1kx4 SRAMs. (similar to 2147 or 2148 types, respectively) The 1Kx4 parts have common I/O, and both types are 18-pin DIPs. These 16K boards use 2147's don't they? Does your diagnostic (whatever it is) tell you which bit is failing? If it can't read the bits, perhaps it's a (1) a failed decoder or (2) it's a failed data bus buffer, or (3) it's a roached address buffer. The only apparent alternative would be a failed RAM. It does smack of a failed on-board decoder, however, since only the one 4K block is failing. If you can't read/write even a single bit in that 4K block of RAM, it's undoubedly a buffer or a decoder. If only one bit fails, it's probably not a decoder, but then the RAM itself is suspect. Since the failure is in the "middle" of your board, it's probably not difficult to compose a loop which cycles through the ram board in 1K blocks, doing a write to one location in each 1K block, first the lsb, then left-shift and do it again, etc. This enables you to trace the device select, and write strobes through the circuit. A 16K board in a 64K memory map ought to be pretty simple to decode. There should be jumpers/switches to select which 16K block in the memory map the board occupies, and there should be a 2-line to 4-line decoder to select the individual bytes of memory. If the organization is as 16 pairs of the 2148-types, then there's probably either a 4 line-16 line decoder (e.g. 74154) or a pair of 2-to-8 types (e.g. 74138) to select a byte of RAM for each memory cycle. Assuming you have the equipment at your disposal, you can determine whether each RAM device is receiving the write and select strobes at the correct times, and likewise, whether they get their enable and select when being read. IF those are both correct, you then write a loop which writes all zeroes to the rams and then having finished writing the zeroes, cycles infinitely on reading them back. You then look to see where the zeroes no longera appear as zeroes, bit by bit, until you have it narrowed down to one data bit and replace the device which isn't transmitting the zero. If they all transmit zeroes OK, then you write all ones out to the ram board and then look for where the zeroes coming from the ram are no longer zeroes. It's not a bad idea to monitor the write operation as well to see that the data makes it TO the RAM in the correct sense, inasmuch as the S-100 has separate in and out busses. This whole process, aside from the associated repair shouldn't take too long and will fix the problem once you isolate and replace the failing component. If, however, you're determined simply to move the failing block of memory to the top where it's easy to ingore, you can switch decoder outputs by tracing back from the failing block of RAM to the decoder and then cutting the traces and soldering on the jumpers which will accomplish what you want. Dick -----Original Message----- From: Mike Noel <Mike-Noel(a)GCI.net> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Friday, December 03, 1999 10:21 AM Subject: Processor Technology S100 memory boards >I'm looking for manuals for Processor Technology 16KRA and 32KRA >S100 memory boards. > >I've a SOL-20 with 1 of each, and the 16KRA has a bad 4k block so I'm >trying to (1) figure out how to reconfig the cards so the bad memory is >at the end instead of the middle, and/or (2) figure out how to fix the >bad card. > >Anyone able to xerox their manual(s) for me? > >Thanks

25 years, 4 months

Basic Source for Super Star Trek

by rcini＠msn.com

Hello, all: Does anyone have a copy of the Basic source for Super StarTrek? It's included in the book "BASIC Computer Games" by David H. Ahl (Creative Computing). I probably won't win the eOverPay auction, so I'm trying to search out a copy of the game, since AFAIK, it's the only program of interest in book anyway. Thanks. Rich [ Rich Cini/WUGNET [ ClubWin!/CW1 [ MCP Windows 95/Windows Networking [ Collector of "classic" computers [ http://highgate.comm.sfu.ca/~rcini/classiccmp/ <---------------------------- reply separator

25 years, 4 months

Intel Intellec 8 computer?????

by edick＠idcomm.com

I remember seeing the promotions for this in conjunction with 8048 development back in the late '70's though I doubt it was exclusively for the 8048. I may have a manual or something lying about, though, now that I want it, I'll probably have a devil of a time finding the thing even though I've stumbled over it several times in the past month. Dick -----Original Message----- From: Joe <rigdonj(a)intellistar.net> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, December 04, 1999 9:44 AM Subject: Intel Intellec 8 computer????? >Hi, > > Can anyone tell me more about what this is? > > Joe >

25 years, 4 months

pdp-11/60 Semi-Rescue

by mcquiggi＠sfu.ca

Hi Gang: Well an 11/60 is going to the scrappers on Monday here in Vancouver. It's at an acquaintance's house, he got it and never got around to getting it set up in his basement. I can't take it due to lack of storage space. Too bad, it's complete, although it's been stored in a garage and not powered up for about 10 years. I am, however, going to save the CPU cards, any other cards, and the backplanes. I will also try to save anything else that can be readily removed from the machine. I did try to find a taker for this beast, as you'll recall from the lists, but unfortunately it's been almost a year and the potential takers have not been able to get around to picking it up. He cannot wait anymore and has arranged for a scrap metal dealer to pick it up this Monday. This is a sad situation, but at least I'll be able to save some of the machine. I'll post to the lists with my results. Kevin -- Kevin McQuiggin VE7ZD mcquiggi(a)sfu.ca

25 years, 4 months

Apple StyleWriter M8000

by chrish＠kootenay.net

Hey all I have an Apple StyleWriter M8000 black and white inkjet printer to GIVE AWAY for the cost of shipping, if anyone is interested let me know. thanx Chris

25 years, 4 months

Great Christmas Gift!

by grrreatgift＠hotmail.com

An HTML attachment was scrubbed... URL: http://www.classiccmp.org/pipermail/cctalk/attachments/19991203/75402273/at…

25 years, 4 months

List spammers located, LARTs launched

by kyrrin＠bluefeathertech.com

Ok... I don't know about the rest of you, but I've about had it up to my eyeballs with the soulless morons who keep spamming CLASSICCMP. I just sent off an E-mail to Derek Peschel asking... 1). That the list be configured to accept DIRECT (unscreened) postings ONLY from subscribers. 2). That I be permitted to volunteer to screen all non-subscriber postings before either (a), passing them on (and if they have even the slightest connection to subjects on CLASSICCMP, be assured that they would get passed on promptly), or (b), tossing them in the bit bucket. Since I seem to be the most experienced spam-fighter in the group (and I'm open for challenge on that), #2 made sense. It would allow me to trace back and LART spammers without their crap ever being seen by the list members. If you have any thoughts on this one way or another, please address them to Derek (dpeschel(a)u.washington.edu) with a CC to me. Thanks! -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Bruce Lane, Owner and head honcho, Blue Feather Technologies http://www.bluefeathertech.com // E-mail: kyrrin(a)bluefeathertech.com Amateur Radio: WD6EOS since Dec. '77 "Our science can only describe an object, event, or living thing in our own human terms. It cannot, in any way, define any of them..."

25 years, 4 months

Tricks with third-party hardware (was Re: VAXstation vs MicroVAX)

by ethan_dicks＠yahoo.com

--- Roger Ivie <IVIE(a)cc.usu.edu> wrote: > Aha! Another VAXBI survivor! And I've got the mounds of leftover crap to prove it! > The company I used to work for did a quad IEEE-488 interface... What an odd thing to make. That's a *lot* of instruments in a small amount of space (owing to cable-length limitations). > ...(imagine a Z80 looking up user-space addresses > in the page table. Fun!) Our drivers were a little different - first, all of our products were 68000- based. Second, we used 1/4th of the address space as shared memory to the VAX as a DMA cycle. Imagine this if you will... accessing 18 or 22 bits of 68K address space would return (or modify) the contents of a real physical memory location in the VAX. I have used one of our Qbus boards and a Fluke ICE tester to check LSI-11 DRAM chips... It works something like this... o Plug into a BA11-N an 11/03 CPU with a row of 4096 DRAMs socketed, a DL11-E, a COMBOARD-Q with the CPU removed and the Fluke plugged into the CPU socket. o Power on the BA11-N, then use ODT to flip a bit in the COMBOARD-Q CSR to enable DMA cycles (safety measure on our part) o Set up the Fluke to test 4K of memory in the "shared memory" quadrant of the 68K address space. o Check the results. I used this arrangement to test 4Kx1 DRAMs for my Z-80-based GORF machine. I have a DRAM tester for 64K and 256K chips, but it only tests single-supply parts. > We sold about a hundred or so IEEE-488 interfaces. As far as I'm concerned, 100 is a handful. My old company made more than ten times as many Unibus cards as that. I think I get one inquiry per year about our old sync products; nothing serious. Who needs to move sync data over 3780, HASP or SNA to or from a VAX these days that doesn't already have a way to do it? -ethan ===== Infinet has been sold. The domain is going away in February. Please send all replies to erd(a)iname.com __________________________________________________ Do You Yahoo!? Thousands of Stores. Millions of Products. All in one place. Yahoo! Shopping: http://shopping.yahoo.com

25 years, 4 months

Help Identify Vacuum Tube Computer Boards?

by bill_r＠inetnebr.com

I dug out some old vacuum-tube-type computer boards I have had in storage since I bought them surplus in the 1970's. If anyone can take a look and tell me what they might have come from, I would very much appreciate it. They are on the link below: http://incolor.inetnebr.com/bill_r/unidentified_technological_artif.htm -Bill Richman (bill_r(a)inetnebr.com) http://incolor.inetnebr.com/bill_r - Home of the COSMAC Elf Microcomputer Simulator, Fun with Molten Metal, Orphaned Robots, and Technological Oddities.

25 years, 4 months

VAX 6500

by oprn＠datamatics.co.in

Dear Ken Peck, We understand that you will be de-installing VAX-6500 somewhere in month of June. We are interested to know its config, version of O/S & the software residing on it. We also be interested to know the cost and other details such as date of purchase & licences of it. If the config suites our requirement we can discuss the other aspects later. Please provide the information to us lastest by 6th December1999 ie. Monday. Thanks & Regards. S.GUNJAL

25 years, 4 months

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test-drb December 1999