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2 x Commodore PET 2001 (1977-1978) Chiclet Repair

Below a short description of the repair.

Commodore PET 2001 (1977) Chiclet Keyboard (#1)

Defect:

  • Garbage Screen on boot and partially in a working state.

Diagnosis/Repair:

  • The Multiplexer 74LS157 (position D2) had an output (pin 4) always been in low state.

Gallery of the repair:

 

Commodore PET 2001 (1978) Chiclet Keyboard (#2)

Defect:

  • Garbage Screen on boot.
  • Memory Problems (1018 Bytes are missing)

Diagnosis/Repair:

  • The garbage screen on boot was caused by a poor contact of the sockets where reside the ROMs. Temporarily fixed by inserting a precision sockets above the original socket (very bad quality sockets).
  • The problem of the missing memory was fixed by replacing a RAM MPS 2114 (position J1) with a new one.

Gallery of the repair:

  1. Mark
    October 30th, 2015 at 18:42 | #1

    Hello, I have some OLD PETS that now is time to start making them work.. Im looking for some assistance and guidance as I go.. I surely hope to get support here. one thing I noticed on your pictures of this repair, is the use of an apparent smaller LCD monitor to display the PET’s video. What did you use (or make) to take the video signal, with vertical and horizontal sync lines to produce a composite video output for use to your LCD ??

    PS: I have two chicklet pets, a 4032, 4016, 8032, 8096 Superpet and I think a 2001 still. 2 8050 drives, 4040 and 2031. Time to get my PET domain alive again.

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