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Recap guide

Recap the Commodore SX-64

In the SX-64, weak or cracked caps in the 12V supply section and around the CRT circuits are linked to a dim picture and a sagging 12V rail.

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.

  • SX-64 board assy 250408-01 (Low confidence). How to tell: Assy number from C64 Wiki. Capacitors: A repair article found the 12V rail drooping under load; no cap values. 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.

  • Sagging 12V rail (Low confidence). One keyboard restoration exposed a 12V rail sagging under load and a cracked filter cap, which was replaced. 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: Blank screen was a stuck data line from the BASIC ROM (Low confidence). An SX-64 with a blank screen was blamed on RAM by a test cartridge, but the real fault was the BASIC ROM 901226-01 holding a data line. The author warns a dead-test flash code only shows a bus fault, not which chip causes it. Source
  • Story: Rolling screen cured by a VIC-II swap (Low confidence). An SX-64 with a rolling internal CRT and black external video was fixed by replacing a bad VIC-II after a PLA swap failed. The author notes some early ceramic VIC-IIs have a raised centre that stops a heatsink seating on the SX-64. 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

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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