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Recap guide

Recap the Apple IIGS power supply

The IIGS supply uses yellow canister electrolytics, two large black electrolytics and .22 uF safety caps that age and fail.

Open the interactive checklist Tick off each capacitor as you replace it. It saves in your browser.

Worth a recap. Reports say it is a common and useful fix on this machine.

Which board do I have?

Boards changed during production. These notes come from the linked sources, and many are only partly documented, so check the board in front of you.

  • IIgs Astec supply (Low confidence). How to tell: Gold cased. Capacitors: 1000uF 10V electrolytics, 0.22uF safety caps, 5 yellow and 2 black cans. Capacitor list differs from other revisions: not known. Source
  • IIgs Dynacomp supply (Low confidence). How to tell: Bare aluminum case. Capacitors: No list. Capacitor list differs from other revisions: not known. Source

Where to start

Clues from write-ups and forum threads, not a diagnosis. Low confidence means one thread or one repair; high means several write-ups agree.

  • Parts to replace (Medium confidence). One thread names five yellow canister electrolytics, two large black electrolytics and two silver .22 uF safety caps, gives a couple of values and recommends a kit. There is no full list. Source
  • Safety caps (Medium confidence). Apple II family advice favors swapping RIFA-type safety caps, and notes the IIc+ Sony supply has none. Source

Tips, tales and maybes

Found in write-ups and forum threads. These are other people's reports, not tested by us. Check part references and values against your own board.

  • Story: Earth leakage breaker trips (Low confidence). An owner whose IIGS kept tripping the earth leakage breaker recapped the Astec AA13591 supply and posted a cap map, but only as image attachments, so values are not in the page text. Source
  • Watch out: Transparent-epoxy film caps and X versus Y class (Medium confidence). A thread says RIFA and WIMA MP3 style film caps in clear epoxy can crack, take on moisture and conduct, and may explode, so replace them with opaque-epoxy parts. It stresses identifying whether each safety cap is an X or a Y class position and fitting the matching class. Source
  • Tip: Load-test the supply and check the small stuff (Low confidence). A poster says IIGS supplies need a load, such as a drive or resistor with a meter, to judge the rails, and that dead ones often have an open 100k resistor or tired electrolytics near the AC input. Dark gold safety caps were called almost always bad and a failed one sprays burning goo. Source
  • Story: Three RIFAs popped (Low confidence). A poster whose supply had already popped three RIFA caps ordered 0.22uF 250V film replacements. A reply recommended replacing the known RIFA problem parts rather than recapping everything. Source

Before you start

  • Boards changed during production. Check your board number against the guides before you order parts.
  • A mains power supply can hold a dangerous charge. If you are not trained to work on one, have a professional do it.

Guides we used

This page and the interactive bench are built from these. They have the photos and the full detail, so please read them and support their authors.

The capacitor list

We have not checked a capacitor list for this machine yet, so none is shown. Follow the guide above for your board, then add the capacitors in the interactive checklist and it builds a shopping list for you.

Skip the sourcing

While you are in there

Affiliate links. As an Amazon Associate I earn from qualifying purchases. These links only search by name. Disclosure

Steps, tools and safety

The steps, the tools in top, middle and budget picks, and the safety list are the same for every machine, so they live on one page: How to recap, step by step.

Values are shown as published in the guides above, and boards changed during production. Check the board in front of you. A recap involves hot tools and, on some machines, dangerous voltages. You do it at your own risk.

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