Vintage Altair 8800 Computer - CONUS For Sale
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Vintage Altair 8800 Computer - CONUS:
$3605.00
If you are looking to restore/expand an Altair 8800 computer, as originally delivered by MITS and unmodified by experimenters, this may be the unit you are looking for. The only deviations from base are the replacement of the MITS four card positions M/80 expander board with a Processor Technology Company MB-1 sixteen card positions mother board and the addition of 256 bytes of RAM to the base 256 bytes on the 1K static memory board.Your are offerding on the following:
- Altair 8800 Computer (Serial Number 220374K)
- 8800 Display/Control Board Assembly
- 8800 CPU Board Rev 1
- 1K Static Memory Board Rev 0 - 512 bytes of RAM
- Power Supply Board
- Power Transformers, Power Terminal Strip, etc.
- Processor Technology MB-1 Mother Board - three of sixteen card positions have S-100 edge connectors installed. This board includes powered bus termination.
- The Processor Technology colored ribbon cable was utilized in place of the MITS provided Display/Control Board wiring.
- Chassis/Case - Small scratch upper right on front panel, scratches lower right on right side, some possible rust on back edge of front frame top (see photos)
- Assembled and tested in accordance with MITS documentation by an experienced Heathkit builder.
- Altair Computer System Documentation in 3 Ring Binder
- Altair 8800 Assembly Manual
- Altair 8800 Theory of Operation Manual & Schematics
- Altair 8800 Operator\'s Manual
- Miscellaneous Information Sheets from MITS
- I have also added the Processor Technology MB-1 Mother Board Assembly Manual to the binder.
- The \'8080\' Programmer\'s Pocket Guide 1977 - Scelbi Computer Consulting, Inc. - 122 Pages
- Tychon Inc. 8080 Octal Code Card (slide rule style)
I built this computer in the Fall of 1975 while attending Electrical Engineering Graduate School. It was a successful build, but I never did much with it. I never got around to adding any I/O. All of my testing and programming was via the front panel switches. The most extensive program I ever ran on it was the music program that uses the computer\'s RFI (not nice!) to play Daisy (Bicycle Built for Two) on a nearby AM radio.
The computer has spent the last decades sitting on a shelf in a climate controlled home office/workshop. I recently decided I should see if there is anyone who can make better use of it. I crossed my fingers and powered it up. What I found was that some component or components have changed in the intervening years such that it does not run like 1975. Occasionally it powers up in a working state and performs beautifully. I can Deposit/Deposit Next in desired memory locations. I can Examine/Examine Next those memory locations. All of the LEDs work showing Addresses selected and Data at selected memory location. I have input a simple routine to add two numbers and have Run and verified desired results at the desired memory address (both in the first 256 bytes and in the second 256 bytes of available RAM). I can Single Step through that routine. When it is operational, I see no issues. Photo 1 shows LEDs during a time when it was operational.
However, it usually does not come up in an operational state. When it has been powered down for some time (capacitors fully discharged?), it generally starts with all Data LEDs lit and all Address LEDs lit. Powering down and immediately back up, generally starts with the INTE and PROT LEDs lit, along with all Data LEDs lit. After a delay, the INTE LED goes dark. After an additional delay, the PROT LED goes dark and all the Address LEDs light up. Whether in an operational state or not, the regulated voltages on all of the cards are perfect. If this behavior suggests to you what the issue might be, please send me a message with your thoughts, as perhaps I could fix it. Or, you could put in a offer for my computer and fix it yourself ...
This vintage computer is being offered AS IS - NO RETURN
