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Commodore PET 2001 – 6550 Ram Adapter by xAD & Manosoft

Commodore PET 2001 - 6550 Ram Adapter by xAD & Manosoft


This adapter replaces all ram installed in the Commodore PET 2001 with a 6264 Static Ram and is useful when one or more ram are faulty. These type of ram are no longer available to purchase.

NOTE: This adapter will only work to replace a chip with a part number starting with MPS 6550. They will NOT replace other RAM types used in Commodore computers other than the original Commodore PET 2001.

The original design was done by Donni of the VCF forum (Vintage Computer Forums).

Unfortunately these pcb have a design problem, below the fix which needs to be done (i always forgot to post this fix, sorry)

Download: Original printable version by Donni (645)

  1. Alex
    December 2nd, 2015 at 23:53 | #1

    Do you sell these boards?

  2. Tombor Jozsef
    January 1st, 2016 at 17:48 | #2

    Could you sell me 1 piece of this board?
    Thanks, Tombor J.

  3. John Duke
    September 19th, 2016 at 21:36 | #3

    I have a PET 2001-N8 , will this replace all the RAM, and where can I buy one.
    Do you have a sugestion for replacing the video RAM as well ?

    Kind Regards,.


  4. giorgio
    January 15th, 2018 at 16:12 | #4

    mi interessa acquistare un adattatore, dove lo prendo? grazie

  5. January 15th, 2018 at 16:25 | #5


    Questi stampati non sono mai stati in vendita perche’ hanno un problema di progettazione e non sono state fatte nuove ristampe.

    Ci sono diverse soluzioni in rete per sopperire al problema delle RAM 6550.


  6. Harrie
    March 8th, 2019 at 15:51 | #6

    Can you tell me what kind of logic chip is used ?
    thanks Harrie

  7. March 10th, 2019 at 01:13 | #7


    Hi Harrie, look inside the .zip of the schematic archive.