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Thread: Apple II replacement power supply

  1. #1

    Default Apple II replacement power supply

    Hi,

    I scored an Apple II which was on its way to the dumpster today. The machine is in great physical condition and the green phosphor monitor still works fine - it displays nicely a movie played through my DVD player composite output! However, the Apple II computer does not work - the fan spins but that's about it - no other signs of life.

    Upon close inspection, I figured that the 12V rail on the power supply is only outputting 9V (and that's why the fan still spins); all other rails read 0V. I believe I could get the Apple II to boot again if only I could find a suitable replacement power supply. The only place online selling it (https://www.reactivemicro.com/produc...ersal-psu-kit/) is asking for 80USD for the board only, plus another 60USD for shipping to Singapore, which is insane!

    Does anyone know anywhere I can get a replacement power supply for a cheaper price? Or short of that, where can I buy a suitable power connector for the motherboard (is there a name for this type of connector?) so that I can modify it to work with an ATX power supply? The plastic on the original power connector has already 'melted', and I am unable to reuse it.

  2. #2
    Join Date
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    Amazing that someone will "throw away" an apple II today, I mean its pretty unique looking apple opinions aside. IT doesn't look like your old beige box.

    There are replacement psu's and kits online. Seems like the asking price is around $85.00 I would just keep using the original. Replace the RIFA's and electrolytic Caps immediately. That's what I'm doing.

    on another note, My Apple IIGS PSU blew a RIFA yesterday. So I had to order more of those. They tend to go far more frequently than the electrolytic variety.

  3. #3

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    Quote Originally Posted by VERAULT View Post
    There are replacement psu's and kits online.
    Do you have a link to one of those sites?

  4. #4
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    Quote Originally Posted by mdanh2002 View Post
    Do you have a link to one of those sites?
    google is your friend... https://www.reactivemicro.com/produc.../power_supply/

  5. #5
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    Blown rifa caps wont stop the supply working they are there to suppress mains noise. Its a good idea to replace them though because they really stink and make a mess when they blow.
    What fan are you talking about? an Apple 2 has no fan.

    Apple 2 power supplies are not difficult to repair. Often replacing the electrolytic capacitors is enough to bring them back to life but that isnt always the case. There are a number of other points of failure that are not uncommon.
    My advice though is to do a recap and if needed a more in depth repair which I can guide you through if needed.
    Its always better to keep them as original as possible.

  6. #6

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    Quote Originally Posted by VERAULT View Post
    This is exactly what I was saying in my original post. It charges 60USD shipping to Singapore. For a small board that is very expensive.

  7. #7

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    Quote Originally Posted by David_M View Post
    Blown rifa caps wont stop the supply working they are there to suppress mains noise. Its a good idea to replace them though because they really stink and make a mess when they blow.
    What fan are you talking about? an Apple 2 has no fan.

    Apple 2 power supplies are not difficult to repair. Often replacing the electrolytic capacitors is enough to bring them back to life but that isnt always the case. There are a number of other points of failure that are not uncommon.
    My advice though is to do a recap and if needed a more in depth repair which I can guide you through if needed.
    Its always better to keep them as original as possible.
    In my case the plastic connector to the board has 'melted'. Do you know where to get a replacement connector? With that I can modify an ATX power supply to work with it.

    The computer has a small 12V fan installed on it, connected via 2 wires coming from inside the power supply (not through the motherboard connector). Maybe it was installed by the previous owner, not from factory.
    Last edited by mdanh2002; February 9th, 2018 at 05:56 AM.

  8. #8
    Join Date
    Sep 2016
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    Westminster, Colorado
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    Quote Originally Posted by mdanh2002 View Post
    In my case the plastic connector to the board has 'melted'. Do you know where to get a replacement connector? With that I can modify an ATX power supply to work with it.

    The computer has a small 12V fan installed on it, connected via 2 wires coming from inside the power supply (not through the motherboard connector). Maybe it was installed by the previous owner, not from factory.
    I'd disconnect the fans for now, they normally aren't needed and present extra load to the supply.

    Beyond that, take the best quality pics of the power supply boards and we can try to suggest fixes for you. Bulging capacitors and burnt components need to be replaced first.

    If you aren't electronically oriented, it's possible you can take the supply to a local TV repair shop (if they still exist) or maker space and see if they can help out.

    An ATX supply may not provide all of the voltages you need. Search online for the Apple II schematics and that will give you the pinout.

    CW

  9. #9
    Join Date
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    Quote Originally Posted by mdanh2002 View Post
    This is exactly what I was saying in my original post. It charges 60USD shipping to Singapore. For a small board that is very expensive.
    Thats why I mentioned you should just fix your existing fauly PSU

  10. #10

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    Quote Originally Posted by Bitly View Post
    I'd disconnect the fans for now, they normally aren't needed and present extra load to the supply.

    Beyond that, take the best quality pics of the power supply boards and we can try to suggest fixes for you. Bulging capacitors and burnt components need to be replaced first.

    If you aren't electronically oriented, it's possible you can take the supply to a local TV repair shop (if they still exist) or maker space and see if they can help out.

    An ATX supply may not provide all of the voltages you need. Search online for the Apple II schematics and that will give you the pinout.

    CW
    I will try to take some photos tomorrow and post here.

    I adapted an ATX power supply to work with a Macintosh LC before. The only voltage rail that is missing is the -5V, which can easily be substituted with a 7905 connected to the existing -12V. I found here http://apple2.info/wiki/index.php?title=Pinouts the pinout of the connector, but it's not clear which side is which - the pins on my connector are not numbered. Besides, I seriously want to replace the connector before performing any further repairs. Does anyone know the name for this type of connector so that I can search on mouser/digikey?
    Last edited by mdanh2002; February 9th, 2018 at 04:45 PM.

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