Recapping an Apple II Power Supply

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Joined: Jul 15 2014
Posts: 42

How would I go about recapping an Apple II power supply? How do I get the board out to replace the capacitors? I would like to be able to repair it, put it together again and install it in my Apple //e to replace the PC power supply hack-job I currently have.

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Joined: May 27 2013
Posts: 794
Re: Recapping an Apple II Power Supply

Extremely condensed version:

1). Remove screws from PSU.

2). Loosen screws on the bottom of the PSU which hold the board in place.

3). Caps that should be replaced are the electrolytics and safety caps.

4). Observe polarity on the electrolytics only.

5). To order the caps for the PSU make sure that microfarad rating matches and voltage rating is equal or higher.

6). Replacement cap should have the same lead spacing, same height or shorter and low ESR is always good.

7). Use soldering pencil to desolder caps and use a desoldering pump or solder wick to remove solder from the traces so that the holes will allow the new cap to be installed.

Assemble the PSU by reversing the steps you used to disassemble the PSU.

If this is too difficult for you to understand then it might be a better idea to get someone else to do the job for you.

I am waiting for someone else to suggest a replacement board to be installed instead of replacing the caps.

Such a suggestion is useless because if you go to a mechanic to fix your car, it's just as useless for him to tell you, "get rid of your car and get a Volkswagen."

1978AppleII's picture
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Joined: Jul 5 2015
Posts: 196
Re: Recapping an Apple II Power Supply

insanitor wrote:

Extremely condensed version:

1). Remove screws from PSU.

2). Loosen screws on the bottom of the PSU which hold the board in place.

3). Caps that should be replaced are the electrolytics and safety caps.

4). Observe polarity on the electrolytics only.

5). To order the caps for the PSU make sure that microfarad rating matches and voltage rating is equal or higher.

6). Replacement cap should have the same lead spacing, same height or shorter and low ESR is always good.

7). Use soldering pencil to desolder caps and use a desoldering pump or solder wick to remove solder from the traces so that the holes will allow the new cap to be installed.

Assemble the PSU by reversing the steps you used to disassemble the PSU.

If this is too difficult for you to understand then it might be a better idea to get someone else to do the job for you.

I am waiting for someone else to suggest a replacement board to be installed instead of replacing the caps.

Such a suggestion is useless because if you go to a mechanic to fix your car, it's just as useless for him to tell you, "get rid of your car and get a Volkswagen."

Also capacitors can hold a charge for awhile. So if you’ve plugged it in recently, let it sit for awhile before attempting or you will get a nasty shock.

I tend to error on the side of caution, and let it sit for 6 hours or so - but that’s likely excessive.

Jennifer

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Joined: Dec 19 2003
Posts: 832
Re: Recapping an Apple II Power Supply

If one does a recapping job like this, and assuming that you get your supplies from a reputable supplier for newish stock, how long are modern capacitors good for? Are they superior to the old ones as far as working lifespan?

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Joined: Feb 17 2013
Posts: 149
Re: Recapping an Apple II Power Supply

Unless you really care about keeping the original power supply, why not simply replace the power supply internals with this?

cbmeeks's picture
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Joined: Jan 17 2005
Posts: 56
Re: Recapping an Apple II Power Supply

I agree the replacement PSU would be the ideal choice. However, if you re-cap the original PSU with good, high-quality caps then would that not be good enough too?

tokabln's picture
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Joined: Dec 30 2015
Posts: 104
Re: Recapping an Apple II Power Supply

You might take a look at the following speedyg webpage:

http://www.appleii-box.de/D04_allabotpowersupplies.htm

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