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Thread: Apple III video issues

  1. #1

    Default Apple III video issues

    Im having trouble with an Apple III that was given to me.

    it has been sitting in a closet for many years and upon powering it up im getting a screen of dots and garbage

    IMG_20200111_194606_MP s.jpg

    i have tried reseating every chip including the ram. i even swapped some around with the same kind on the board and nothing has changed. i also swapped the ram around too.

    voltage from the powersupply is looking good. and the on light on the keyboard is good.

    some of the chips and a few more rams chips had tarnish on the legs and i cleaned all that up.

    i dont seem to have the chip populated at b3 but i think its a real time clock.

    im not sure where to begin.

  2. #2
    Join Date
    Mar 2014
    Location
    Los Angeles
    Posts
    128

    Default

    Quote Originally Posted by nicko6113 View Post
    Im having trouble with an Apple III that was given to me.

    it has been sitting in a closet for many years and upon powering it up im getting a screen of dots and garbage

    IMG_20200111_194606_MP s.jpg

    i have tried reseating every chip including the ram. i even swapped some around with the same kind on the board and nothing has changed. i also swapped the ram around too.

    voltage from the powersupply is looking good. and the on light on the keyboard is good.

    some of the chips and a few more rams chips had tarnish on the legs and i cleaned all that up.

    i dont seem to have the chip populated at b3 but i think its a real time clock.

    im not sure where to begin.
    i got a similar issue and i havent been able to fix it for years. I'm following this in case you figure it out one day

  3. #3
    Join Date
    Apr 2011
    Location
    San Francisco, CA
    Posts
    511

    Default

    Do you know what type of memory board your Apple III has?
    Something reasonably easy to try is seeing if there's one or more bad RAM chips. Depending on which type of memory board you have, it may be 4164s (relatively easy to find). The 12v board has a more exotic DRAM, which I can't recall exactly, but you can replace one of them with 2 more common DRAMs piggybacked with a jumper.

    If you can post a few pics of the III motherboard, that may be helpful. Also bad ROMs are a likely possibility.

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