directory of MITS Altair 680 pictures:

  • top/front corner view, main board - 680 MAIN BOARD REV 1-6X
  • same, closeup
  • same, another closeup of board ID
  • same, another closeup
  • front panel of MITS Altair 680. Compare colors with Byte back cover July 1976
  • another front panel picture of MITS Altair 680.
  • front panel of MITS Altair 680 (grainy pic).
  • MITS Altair 680 Main board view.
  • Altair 680 rear view. Apparently there once was a serial card installed in this unit.
  • MITS Altair 680 Main board view.
  • MITS Altair 680 serial number E11952.
  • View of 6800 and 6850 main board chips

    2/15: I am currently researching for a way to toggle in instructions to activate the serial port, and instructions to test the RAM.

    2/21: Received ACIA prom from Steve Shepard.

    2/25: Referring to ACIA Monitor Manual set memory for FF02 to start monitor. With help of Steve Shepard learned how to toggle through FF00-->FF0D to compare lights with expected data bits. Matched. Did not continue through to FFFF.

    2/28: With help from Steve Shepard, learned that IC in position L, 74L123 is missing. Steve suggested that I review every chip and connection to be sure nothing else is missing/incorrect. I am in the process of doing this now.

    Here is the manual:
    Theory of Operations

    3/1: Here are the hi-res pictures I am using to review motherboard and front panel board:
  • Front Panel, inside left
  • Front Panel, inside right
  • Motherboard
  • IC L missing (74L123)
  • RAM view and ACIA courtesy of Steve Shepard
  • RAM jumpers set to 0000 (1 K)
  • IC's RR through ZZ and hardware jumper view
  • Processor and baud rate jumpers (1200 baud)
  • Hardware Programmable Jumper (No Baudot, 2 stop bits, terminal)
  • Hardware Programmable Jumper View 2
  • Hardware Programmable Jumper View 2
  • Hardware Programmable Jumper View 2