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Thread: Apple /// power supply schematic

  1. #1
    Join Date
    Aug 2008
    Central California

    Default Apple /// power supply schematic

    I left an Apple 3 sitting there running memory tests while I went to the store. I came back to the biggest stink and clouds of smoke. C1 had decided to blow up in spectacular fashion. Nothing left but, a melted mass and a stink I cant get out of the table. If nothing it was a wakeup not to leave 20 year old electronics running unattended. Obviously it could have ended worse.

    I'd love to give it another try and see if I cant blow up another one but, not enough left to see what its ratings were.

  2. #2



    Yea, I don't like to leave my vintage models running unattended for that very reason. Which is why they don't get as much of a regular workout as they should.

    My vintage collection:
    My vintage activities blog:
    Twitter: @classiccomputNZ ; YouTube Videos: (click here)

  3. #3


    C1 is the same as C7 - 2200pf.

    Technically you can run the power supply without it, but it's best to have it. You either got a power surge or the thing just decided to short the plates across the dielectric.
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  4. #4


    I had the same thing happen to one of my A3s although I was standing there at the time. . .

    It was an easy fix, too. . .

  5. #5


    Happened to me twice
    @ BillDeg:
    Twitter: @billdeg
    Youtube: @billdeg
    Unauthorized Bio

  6. #6
    Join Date
    Aug 2008
    Central California


    Thanks for the info. Its an easy fix if I can figure out a way to stand the smell long enough to fix it

    Three days later and the smell still makes my eyes water if I get too close to it.

    I wouldn't think a surge as it had been running continually for about 20 minutes before it happened.

  7. #7


    It's not a surge issue. It's just an old cap that warmed up, cracked and then smoked some oil.

    I know the smell well.


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