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Recap guide

Recap the Macintosh IIci and IIsi

The IIsi is notorious for leaky caps, and both the IIsi and IIci have power supplies that need recapping.

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.

  • IIci supply, Astec (Low confidence). How to tell: Maker named on the supply; a console5 note warns not to trust the 614 or 699 Apple numbers and to check the real maker. Capacitors: No values in the thread. Capacitor list differs from other revisions: not known. Source
  • IIci supply, GE 9T89Y5005G11 (Apple 699-0392) (Medium confidence). How to tell: GE model number on the supply. Capacitors: A recap kit exists for it; no values in the thread. Capacitor list differs from other revisions: not known. Source
  • IIsi supply (Sony) (Medium confidence). How to tell: Sony supply of about 1991 in one article. Capacitors: 12 electrolytics: 2 SMD on a daughterboard and 10 through-hole, including a 400V cap in the AC section. 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.

  • IIsi power supply (Medium confidence). One write-up counts 12 caps in the IIsi PSU, including two SMD on a daughterboard and a 400V part. The author recapped only 3 of the 12 and defers to a repair service's list for values. Source
  • Leaky IIsi board (Low confidence). A logic board testing thread confirms the IIsi's leaky-cap reputation and the split between PSU and board problems. Source
  • IIci supply (Low confidence). A request thread for the IIci supply points to a wiki list and a Console5 kit for Astec or GE supplies. 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: Five IIcis, five leak patterns (Medium confidence). A refurbisher reported five IIcis that all showed electrolytic leakage, with lifted pads at C2 and C3 near the sound chips, corroded 74HC132-family logic chips, battery damage on one and contamination on another. He replaced leaked logic chips and advises replacing the 74ALS240 below C16 if NuBus slots fail. Source
  • Story: Shutdown after hours traced to leak damage (Low confidence). A IIci recapped with tantalums still shut down after hours, and the cause was broken traces around UE13 and UD13 plus a failed 74HC132 at UE13, found by continuity testing. Leaked electrolyte had hidden damage beyond what was visible. Source
  • Tip: Alcohol bath after caps are off (Low confidence). One restorer received a IIci with the surface-mount caps already removed but corrosion remaining and a badly leaking PSU. He replaced every cap, cleaned the board in an isopropyl alcohol bath and serviced the floppy drive. 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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