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Thread: Film capacitor Apple II+/e power supply

  1. #1

    Default Film capacitor Apple II+/e power supply

    There is a .1uF 250V film capacitor that has burnt or blown out in several of my Apple ii computer power supplies.
    It is easy to get to in the Astec and the Dyna, except the Dyna has two of them. They are a simple replace.
    I am having trouble finding a supplier that has the correct one here in the US.
    Any one know of the exact part I am talking about and where to get them?

  2. #2
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    By the sound of it, it's just a line filter cap, which should probably be a safety (X- or Y- rated) capacitor. Polyester or polypropylene versions generally age better and are not expensive, so unless you're picky about "original parts", it should be a simple matter.

    Got a photo of an old one?

  3. #3

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    Thanks Chuck(G) - no sharp photos that you could tell much from. The caps are quite toasty as well.
    The information on the cap is as follows:RIFA 40/85/56 fe=4,9 250V 0,1uF@X
    Forgive me my component electronics education is way in the past, I can solder and keep these old Apple girls alive though.
    I hope this gives you something to go on.
    Many thanks!

  4. #4

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    Check mouser part 539-158X104K - I think that's what you're looking for.
    http://www.mouser.com/ProductDetail/...r-CDE/158X104K

  5. #5

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    Speak of the devil ... The same thing just happened to me tonight. I was testing a board and after a few minutes heard / smelled it. Shut it off before the program even quit running.
    Now the room reeks. I see that cap burned through the side. Guess I'll be ordering that cap too. I see a few others swelled as well.

    Larry G

  6. #6
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    David's got the right part, even though the infamous Rifa caps are usually encapsulated in clear or yellow-brownish resin. The important part is the "X2" safety rating.

    It happens more frequently than one might think.

  7. #7

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    I've got the caps on order but still question whether the RIFA cap is even necessary. If it's purpose is to keep RFI from travelling back out the AC mains, does it even matter anymore? Who uses analog TV or radio anymore in the home? I'm tempted to just snip it out. I bet it would work just fine. Having an RIFA cap seems like a problem just waiting to happen ...

    PS - hmmm, unless it keeps the display from getting squirrelly lines ...

    Larry G
    Last edited by retrogear; March 17th, 2016 at 08:38 AM.

  8. #8
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    Quote Originally Posted by retrogear View Post
    Who uses analog TV or radio anymore in the home?Larry G
    Want to guess what Wifi, and OTA Digital TVs use?

  9. #9

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    Quote Originally Posted by retrogear View Post
    I've got the caps on order but still question whether the RIFA cap is even necessary.
    The computer itself will run just fine without it. That said, I always replace mine. I have a baggie each of the .1uf for the II line and .22uf for the /// line.

  10. #10

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    Thanks david. I don't like waiting for parts so I might try removing it and see if the family complains about the wifi performance

    PS - come to think of it, my workbench is not too far away from the wireless router ...

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