test-drb September 1998

test-drb@ccmp.vtda.org

154 participants
649 discussions

by ddameron＠earthlink.net

Hi Sam and all, At 11:34 AM 9/9/98 -0700, you wrote: > >If you're not aware of this, Don Tarbell, of the famous Tarbell Cassette >standard, died earlier this year. Someone posted about this on the list >around the time he passed on. > I called Don about 18 months ago asking if he could give me some information on his earlier homebrew computers. I know he started in the mid 1960's with a RTL (resistor transistor logic) system. He didn't know where to locate any at that time. I also said I'd be interested in other earlier computer literature. I knew a little about his cassette interface from BYTE ads. He and his wife Brenda took my mumber. Well this week she called, She had taken care of most things and was moving this Sat. She had a small box of literature that I could pick up if I wanted it. I said Sure! The box has several of the Micro 8 newsletters, some IMSAI stuff, some 1977 Bytes, source code listings for Processor Tech Basic-5 and Software package No. 1, +... I was happy to have found it. Her last trash pickup would have been the next day. Why I'm writing is thrown out at the street was his (their) last homebrew computer, "PUTER". Brenda said I was welcome to it. She had spent many hours soldering the boards, they had dropped all work on it when the Altair came out. I would like to get it to do at least something. The problem which makes it (maybe too) difficult is that ALL documentation is lost. Many wires are broken. I have 3 units: 1. the rack "mainframe" which include 16 address lights, 8 data switches, 4 "file address" switches + about 10 others. The main power supply is 5V, 15 Amp. The backplane has space for 16 cards. There are 8. 2. A spare? cardcage with 7 misc I/O cards? The edge connectors are wired partially, but it looks like a card storage unit. 3. A "GA" logo core memory card, 15 x17 inches (38x43cm). Not sure if it was connected. Brenda said Don collected all types of computer surplus for his projects. I left behind a hard disk unit in a rack in very poor condition. The single platter had been exposed for over 10 years... Most of the cards are Douglas Electronics 11DE5. (They are in San Leandro in N. Ca. and still sell these. You can see their line at www.douglas.com. they also sell DEC, S-100 and other form cards at attractive prices, in my opinion, if anyone needs them.) The cards 11DE5 hold up to 36 16 pin dips. They are soldered together with vari-colored telephone wire. (AWG 24, about 0.5mm). Am example of what I have is a serial card (from the DB-25S) which contains 20 IC's. 3-7401 2-7402 2-7404 1-7421 1-7427 1-7430 1-7442 2-7474 2-7496 5 bit shift reg. 1-74163 1-74180 parity gen. 2-9602 (T. and R clocks) 1-8273 10 bit shift register. This was in the "spare" cardcage. Have not traced this board circuit or any other yet! May start with a simple one with only 8 IC's. Have not recognized any computer function yet, such as a ALU, address latch, etc. Should I start by finding the data and address busses on the backplanes? Or does this sound like an impossibly long task??? Brenda said this system was used to start development on a cassette system before S-100 came along. It is really amazing that he interfaced a hard disk to it and wrote an operating system for it. She said one output devicer was an X-Y recorder. If anyone has any of the Amateur Computer Society issues that have any descriptions, I would be very interested. -Dave

26 years

Monitor repair

by allisonp＠world.std.com

Here's one that has me going... Gateway2000 crystal scan (1572 FS): Problem: display from cold start is 75% of normal size, warms up to normal after about 10 minutes. Color and aspect ratio excellent as is focus even in shrunken form. Chill spray on components cannot cause the display to shrink. Any clues on this one? I have no prints... As tubes go this one is fairly nice. Allison

26 years

Monitor repair

by roblwill＠usaor.net

Speaking of monitor repairs, does anyone know how to get rid of that annoying whistling that some of the older monitors have? I have an old Magnavox that is a GREAT monitor (CGA/Herc/Composite, color/green w/ built-in sound), but it whistles like a tea kettle (O.K., that's a bit exaggerated, but it's pretty bad). I've been told to put glue on the flyback, but where? Also, speaking about that monitor, there's two sockets on the back: TTL RGB Lin RGB I have the TTL RGB cable, which will work with CGA (standard 9-pin). I don't have the Lin RGB cable, and the connector for it is a 6 pin DIN jack (the one for the TTL RGB is also an DIN connector - 8-pin). What is the Lin RGB for, and what is the pinout for it? I got the monitor used for two bucks, so I don't have a manual. ThAnX, -- -Jason (roblwill(a)usaor.net) ICQ#-1730318

26 years

Where to find Vax stuff in Mass.

by allisonp＠world.std.com

< Sounds like a dumb question and probably is. I have moved from Chicago < to a small town in < Massachussetts (Randolph). Is there a "junkyard" where one can find Va < stuff? There maybe but I don't know of one. I'm down the road in Framingham. Being as eastern MA used to be called the "greater Maynard area" by DEC people (Digits) there should be more than I see around. They arent scarce either. Colleges are a good place to look. Allison

26 years

IBM 1130 Was: Re: Linux on S/370? Was: Re: printer socket (Off topic)

by cfandt＠servtech.com

At 23:08 22-09-98 -0400, you wrote: >> Yeah man! Where???????!!!!!!! I'll rent a tent and camp out at the place >> which has one until either they get tired of it or that Y2K thing obsoletes >> it. W. Donzelli would be camping right next to me I think. > >No, I will be letting the air of your car's tires. Oh no you won't ;) I'll get a set of those new Michelin Zero Pressure tires (ones which the TV ad shows a 3/4" hole being drilled in the sidewall and the car driving away; 55 MPH for 50 miles... [howzat work anyway?]) > >> Seriously, that would be, in my opinion, the most excellent find! As I >> mentioned, I have never heard of any around these days. They were, I >> believe, not the typical mainline computers one would hear of in business >> like the S/360's and S/370's. Weren't they more used in R&D and academia >> because of their ability to handle number crunching not so much as >> databases like a business application would? > >I know little about 1103s, but they were indeed built for number crunching >for people that could not afford a big S/360. The 1103 is related to the >1800, used for process control (leading to the S/7). You must have been tired at 23:08 when you wrote this :) It's an IBM 1130. Since the 1130 is related to the 1800, I would like to lookup info on the 1800 machine. Any online leads? --Chris -- -- Christian Fandt, Electronic/Electrical Historian Jamestown, NY USA Member of Antique Wireless Association URL: http://www.ggw.org/freenet/a/awa/

26 years

Removing mailing label gunk

by manney＠lrbcg.com

An Epson gas eaten several mailing labels over the years (I think at least _some_ of the labels must be 10 years old!). What's good stuff to remove the gunk without melting the plastic? Thanks, manney

26 years

More monitor Repair

by lwalker＠mail.interlog.com

While we're on monitor repair: I picked up an IBM PS/1 SVGA which when turned on flashes a normal screen for less than a second, which collapses and then displays a slowly degrading squiggly vertical line which gradually shortens and blanks. Likely some classic symptom . Any ideas ? ciao larry lwalker(a)interlog.com

26 years

Monitor repair

by allisonp＠world.std.com

< I have the same monitor. Don't have the same problem, though. It may b < just the picture tube warming up, which would explain why the chill spra < doesn't do anything. Although 10 minutes seems like an awfully long tim < for tube warm-up. Mine gets to full size, and warmed up in about 15 < seconds. It's from 1992 (or93). This is fromn a friend and was retrired because this wasn't normal operation. The tube should be warm in a minute or so but the diplay growth takes a good 10-15minuts to reach normal. It is otherwise stable. It's in very good shape but is was used every day for over 4 hours a sitting. My first thought was power supply but any point I've measured is stable on warm up. Allison

26 years

EDSAC on your desk.

by tomowad＠earthlink.net

>A simulator (in general) preserves one aspect of the machine - a platform >on which to run the original programs. What it doesn't preserve is any >feel of the hardware, any of the hardware techniques that were in use at >that time, the construction methods, etc. Have you seen the Apple II emulator 'II in a Mac' for the 68000 Macs? It placed the moitor, a keyboard, joystick, four floppy drives, printer, and a clock on the screen. Then you could actually click on the keyboard's keys or move the joystick on the screen with the mouse. A really neat interface which, IMHO, did a half decent job at preserving the hardware's feel. It's a shame more emulators don't do such a good job at portraying the hardware. Tom Owad -- Sysop of Caesarville Online Client software at: <http://home.earthlink.net/~tomowad/>

26 years

Quantum Q540 as a RD52

by CLASSICCMP＠timaxp.trailing-edge.com

>Thank you from me too, Tim!!!! You're welcome! > I'm going to later this fall/winter try to >start-up my MicroPDP-11/73 and MicroVAX-II machines (along with an 11/34A, >11/24 and 11/23, maybe the VAX-11/730.) Of course, there are a couple of >RD's involved within the uPDP and uVAX here. I've been slow in putting RQDX3 details on sunsite's PDP-11 archive, I will admit, mainly because I despise RD-series MFM drives. Most of this is because I don't get called in until the RD drive is very sick and dying, and of course the users didn't make any backups for the past decade! You better believe that I charge a sizable fee for data recovery/system restoration in this case! -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology Voice: 301-767-5917 7328 Bradley Blvd Fax: 301-767-5927 Bethesda, MD, USA 20817

26 years

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test-drb September 1998