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Recap guide

Recap the Macintosh Classic and Classic II

Both boards leak: the logic board has SMD electrolytics, and the analog board's through-hole electrolytics need attention too.

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.

  • Classic logic (digital) board (Medium confidence). How to tell: One article says there is only one production variant of the Classic digital board. Capacitors: 1x 1uF 50V SMD and 7x 47uF 16V SMD. Capacitor list differs from other revisions: no. Source
  • Classic analog board 630-0395, early with 1000uF 35V at CP2 (Medium confidence). How to tell: Assembly number 630-0395; the unit shown is dated February 1991. Capacitors: A Tinker Different reply says the commonest US version has a 470uF 50V cap at CP2 instead of 1000uF 35V; this board has the 1000uF 35V part. Capacitor list differs from other revisions: yes. Source
  • Classic analog board, common US version with 470uF 50V at CP2 (Low confidence). How to tell: Check the cap fitted at CP2. Capacitors: Same set otherwise; analog board set in one article: 4x 1uF 50V, 1x 4.7uF 250V, 1x 10uF 25V, 3x 47uF 25V, 2x 220uF 50V, 5x 470uF 50V, 4x 1000uF 25V, 3x 2200uF 16V. Capacitor list differs from other revisions: yes. 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.

  • Logic board SMD caps (High confidence). One restoration replaces the Classic's 8 logic board SMD electrolytics and lists parts for both boards, with photos of the damage. A second walkthrough also covers the 8 caps and a tantalum swap. Source
  • Polarity warning (Low confidence). A cautionary analog board thread reports a polarity mistake that popped a 470 uF cap, and also suggests replacing two diodes and the opto. 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.

  • Watch out: Kits differ by board revision (Medium confidence). A Classic owner got a kit built for board 630-0560 while his board was 630-0395. The thread says CP2 needed 1000uF 35V rather than the kit's 470uF 50V, and CL1 differs by revision too (10uF 50V on the 630-0395). After fitting the right caps and a new TEA2037A the vertical collapse remained. Source
  • Watch out: Polarity and pop-after-recap on the analog board (Medium confidence). A thread on a Classic with no chime and glitching video lists backwards electrolytics as a frequent mistake, and says the 470uF 50V cap often fails, sometimes popping at power-up after a recap. Replies advise scrubbing residue with a toothbrush and swabs and checking the 5V rail stays above about 4.75V. Source
  • Maybe: Diodes and opto near the regulation loop (Low confidence). In the same thread replies suggest, when voltage regulation is flaky, also replacing the 1N4148 diodes DP3 and DP4 and the opto-isolator OP1 (a CNY17G), and checking the PP1 pot. These are repair suggestions from posters, not confirmed fixes. Source
  • Tip: Burnt TDA4605-3 usually follows dead caps (Medium confidence). A Classic repair page says to recap the analog board first because failed capacitors often burn the TDA4605-3 control IC, and suggests an LTV702 for the CNY17-3 opto and a diode-check on QP2 when the fuse blows. It also notes the board is very prone to battery leak damage. Source

Before you start

  • Boards changed during production. Check your board number against the guides before you order parts.
  • A tube and its high-voltage circuit can hold a lethal charge. Do not open the tube, and leave the analog board to a professional.

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

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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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