test-drb

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101090 discussions

by allisonp＠world.std.com

<Pardon my ignorance, but what's an R6500? That wouldn't be an IBM <RISC machine, would it? No, non-ibm as it comes. It was the series of chips starting with the 6502 that wree used in the apple series, AIM, KIM, PET and Commodore machines. The number of hands the licensed 65xx chip design passed through is somewhat record as well! Allison

28 years, 4 months

a brain... my kingdom for a brain?

by allisonp＠world.std.com

<a) What should I be looking for in a logic probe. Any recommended model <(say, <$100) Unless the logic is fast (altairs arent!) any will do. <b) Ditto for multimeter. My favorites are a fluke m12 (digital) and a triplite-160(analog). <c) Where can I find a brain? :) think about it for a while ;) <I have it firing up and basically behaving, but some LEDs don't light whe <they should, but are definitely able to light when they want to. Nominal altair misbehavour. Several problems very likely some age and some design related. Switches are not making(corrosion internally), operating them may clean them up or replacement may be needed. Check with low current/voltage continuity tester(fluke m12 is good here). The pannel uses oneshot timers by the carload (74ls123 and friends) and they can be flakey. The mother board connections can be nasty from using solderplated edge connector board with gold edge (electromigration). The board edges can be cleaned with eraser but most systems with that disease end up with shake well before using (pull boards/reinsert to wipe contacts). I highly suggest this for any kit constructed altair pannel: 1. get drawings/schematics 2. clean well a. remove and disassemble to just the board with no hardware. b. Wash (yes really!) in dishwasher (best done when wife is not around) using some of the normal dish washer soap. NOTE: this will remove grime and any flux residues that may over time have become conductive or corrosive! We have no way of assuring a kit was constructed with quality solder/fluxes. c. dry well using WARM oven at 120-140F. (alternate is to soak in pan of 90% or greater isopropanal and air dry. NOTE: ISOPROPANAL IS FLAMMABLE) 3. Inspect and resolder any questionalble joints, use care. 4. Reassemble partially, to allow testing. NOTE: ONE MOD IF NOT DONE IS STRONGLY SUGGESTED... The 8800 front panel design has 120vAC power on it and that was/is very bad practice. As implemented it is a safety hazard and also a risk to the hardware. It is best to keep good distances between mains power and logic! Rewire so that the front pannel power switch is not connected to anything and mount a replacement in a protected spot on the rear pannel. I feel strongly about that, even as a museam peice it should be done. The existing switch can be left in place for appearances. Allison <A < <>Hmm... I've yet to find a classic computer fault that could not be <>tracked down using 3 things - a logic probe, a multimeter (DMM/VOM) and <>a _brain_. On the grounds that my brain isn't that good, I sometimes hav <>to use other test equipment, but when I finally do track down the <>problem, I generally realise that the symptoms were obvious from the <>start if only I'd realised what they meant. < <

28 years, 4 months

front panels

by allisonp＠world.std.com

<I may be in the running to buy an 8800b turnkey model which (sigh) doesn' <have the nice front panel that you describe for the 8800b. Can you tell <me how the turnkey works? Does it have a ROM'd bootstrap loader? Will <be able to program it if I don't have drives? The fronpanel less version of the MITS was the 8800b (turnkey) and it was generally configured to boot their disks. There may have been boot options for cassette or papertape boot as well. Allison

28 years, 4 months

Altair price check

by jfoust＠threedee.com

A few weeks ago, I turned down an offer to get an IMSAI and Altair system, reasonably intact, both for $500. What do I know. :-) Looks like a market ripe for wheeling and dealing. These online auctions are an interesting phenomenon. At first I thought they'd be a great place to pick up contemporary and antique computer stuff at good prices, perhaps with a few "sleeper" bargains. But the info flow is too good; it's my impression that prices are consistently driven *higher* than I'd regard as "street" price. Good news for people running auction services that take a percentage. - John Jefferson Computer Museum <http://www.threedee.com/jcm>

28 years, 4 months

IMSAI 8080 <> TRS-80

by bill_r＠inetnebr.com

Did anyone besides me notice that, judging by their ad in the latest issue of Computer Gaming World magazine, the software division of Metro Goldwyn Mayer (MGM INTERACTIVE INC.), producer of the original "Wargames" motion picture, doesn't know the difference between an IMSAI 8080 and a TRS-80? Their ad goes something like "In 1983, a teenage computer hacker almost destroyed the world with one of these: [picture of TRS-80 Model 1, with caption reading 'TRS-80, 4K RAM, no hard drive']". It goes on to talk about how much damage he could do with today's computers (go figure), and introduces their new "Wargames" computer game. Maybe the marketing department should jog down to the film vault and watch the movie, because _it_ used an IMSAI 8080 with a piece of paper stuck over the name for the young "hacker's" computer. Sheesh. -Bill Richman bill_r(a)inetnebr.com http://incolor.inetnebr.com/bill_r (Home of the COSMAC Elf Simulator!)

28 years, 4 months

e-mail address change

by manney＠nwohio.com

My e-mail address is now -- manney(a)lrbcg.com Let's hope the listproc gets it right, too! P Manney

28 years, 4 months

Computers that have appreciated (RE: Altair price check)

by KFergason＠aol.com

In a message dated 2/23/98 3:04:18 PM Central Standard Time, adept(a)Mcs.Net writes: > > I assume you mean machines that are worth more than their original purchase > > price. That would be a pretty short list... notably: > > > > - RCA COSMAC VIP (ditto) > > Hmm, whats one of these worth? I have 4 of them, but I have never seen any for sale. Kelly

28 years, 4 months

HP 935

by fmc＠reanimators.org

Adam Jenkins <adam(a)merlin.net.au> writes: > Anyone know what a HP 935 is? I assume it to be a Hewlett Packard laptop > of some sort, with an LCD display, but I don't know if it is MS-DOS, > CPM/M, a full laptop or one of the Tandy Model 100 computers, or what. :( I dunno, that makes me think HP 3000 series 935, which is a mini. Either that or they left out the "8" in 9835 and it is a desktop computer, possibly with a one-line LED display (9835B) or with a CRT display (9835A). Well, those are my guesses. I'm interested in hearing how far off I am. -Frank McConnell

28 years, 4 months

old SCSI controller

by rexstout＠ptld.uswest.net

The only things I know about this board is that it's a SCSI controller, and it's BIG. It's about 10"x12", has an 86-pin edge connectr on the bottom, two 50-pin edge connectors on the top, and uses eight 2651 SCSI chips. It's labeled "DATASTREAM ASSY 100716 REV A". Does anyone have any idea what this is for? TIA -JR http://members.tripod.com/~jrollins/index.html - Computers http://www.geocities.com/Area51/Lair/1681/ - Star Trek

28 years, 4 months

Recent Finds...

by foxnhare＠goldrush.com

This weekend's recent finds netted me two books: The first is called Computers and Man, by Richard C. Dorf, published by Boyd and Fraser Publishing Co. in 1974. It looks like it could have been a college text at one time. The real notable part is it is loaded with alot of pictures of earlier machines and computers from the late 60s and early 70s (such as a picture of an IBM 2321 strip file, which I think was mentioned here a few months back.). also a good description of core memory (which I have been searching for to go with my core memory board I won at VCF.) The other, which may be a duplicate (for me) was PET/CBM BASIC Programming and Applications by Gene Streitmatter and Larry Joel Goldstein published by Brady Books which had an unlabeled 5 1/4" disk shoved in it, the disk contained a few examples from the book written by the last owner (for the PET)... You never know what you may find though. Not as bad a Programming books of the time go, even some nice type-in games in the back. Larry Anderson -- -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- Visit our web page at: http://www.goldrush.com/~foxnhare/ Call our Commodore 64 BBS (Silicon Realms 300-2400 baud) at: (209) 754-1363 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

28 years, 4 months

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