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Thread: Commodore Pet 2001-32 looking for replacement roms chips and other issues

  1. #11

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    Quote Originally Posted by MikeS View Post

    It might still be helpful if you listed the part numbers of the various ROM chips and their locations.

    m
    From the pictures, the board has basic 3 plus an addon ROM which is missing a few pins anyway.
    The screenshot shows that the CPU isn't running (or for not enough long) meaningful code and the video generation circuit is also faulty (superimposed characters on the same cells).
    There're many sockets added on logic chips, that means probably that someone "was there" before and indeed might have introduced new problems.
    I would test the ROMs with a programmer and substitute the white sockets as a first step.
    Then I would probably turn on the oscilloscope
    Frank

  2. #12

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    Just want to throw out that those chips with missing pins can sometimes be repaired with salvaged pins from other donor chips and re-tinned as well. I have went so far as using a dremel to expose something to solder to on rare chips. Here is an example:



    Another:
    vlcsnap-2017-11-16-21h08m51s022.jpg
    Last edited by norm8332; May 7th, 2018 at 02:54 PM. Reason: adding

  3. #13
    Join Date
    Dec 2005
    Location
    Toronto ON Canada
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    Are we talking about one system or two?

  4. #14

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    I ordered that Pet tester and I'll try it out when I receive it. I will work on testing the rom chips out on my programmer to read them and I'll work on changing the white sockets. I have two pets that have the same scrambled graphics.

  5. #15

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    Quote Originally Posted by iz8dwf View Post
    Well.... some brands of 2532 can be found on ebay for about $2 each (HN462532 for example) and they won't look ugly like a 2732 with adapters.
    Does anyone her has experience with this EPROM types (I think HN stands for Hitachi)?
    I tried some brands but the only one that works reliably in my PETs is the Texas Intruments TMS2532.

  6. Default

    He makes a replacement video RAM board

  7. #17

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    I have received the tester and tried it out today. I still have the graphics mess on one of the Pets so far. I am thinking the video rom chip is bad or possibly the video ram. I am uncertain as to which chip is the video rom?

  8. #18
    Join Date
    Feb 2009
    Location
    Southern California, USA
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    2,384

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    Quote Originally Posted by Turboman View Post
    I have received the tester and tried it out today. I still have the graphics mess on one of the Pets so far. I am thinking the video rom chip is bad or possibly the video ram. I am uncertain as to which chip is the video rom?
    The Character Generator is P/N 901447-10 in position F10. Use a 2716 EPROM to replace. Zimmers has the binary file needed called "characters-2".

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