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Recap guide

Recap the Commodore 64 and 64C

Board electrolytics are often fine, but a recap is common preventive care. The power brick is potted and is usually replaced instead.

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

Check first. A recap is not always the answer here, so look at the guides before you order parts.

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.

  • C64 assy 326298 (silver label) (Medium confidence). How to tell: Earliest breadbin board with 5 pin A/V output (c64-wiki); revisions 6, A, B, C. Capacitors: A shop kit for this board has 18 electrolytics plus a ceramic restore key; individual values not shown. Capacitor list differs from other revisions: yes. Source
  • C64 assy 250407 (Medium confidence). How to tell: 1983 breadbin; revisions A to C; 8 pin video; common board. Capacitors: Not itemised in sources read. Capacitor list differs from other revisions: not known. Source
  • C64 assy 250425 (long board) (Low confidence). How to tell: 1984 board with single 8701 clock IC; a comment says rev B has an extra disc cap next to C15 beside the 6569. Capacitors: A cap mod guide uses this board; sellers list sets for it but without values. Capacitor list differs from other revisions: not known. Source
  • C64C assy 250466 (Medium confidence). How to tell: Early C64C with two 64Kx4 RAM chips and horizontal fuse behind the cartridge port. Capacitors: No cap list found. Capacitor list differs from other revisions: not known. Source
  • C64C assy 250469 (rev 1, 3, 4, A, B) (Medium confidence). How to tell: Short board, vertical fuse, 64 pin custom chip. Capacitors: Power section differs: single 5V rail, and SID 9V and 12V made by a transistor circuit, so regulator related caps differ from older boards. 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.

  • Ripple on the 5V rail (Low confidence). One write-up explains why old caps with high ripple matter, and describes ripple on the 5V line killing chips. It has no parts list. Source
  • Parts choices (Low confidence). An element14 video page offers a partial bill of materials with polymer and ceramic choices. 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: Regulator failure sends too much 5V (Medium confidence). The C64 wiki says the main danger of old bricks is over-voltage on the 5V line that destroys the computer. It documents only the screwed-together 902503-02, lists regulator options 3052P, NTE1934 and LM2596, and a 4700uF 16V cap, with an electrocution warning for the mains terminals. Source
  • Tip: Cracked regulator joints and mild undervoltage (Medium confidence). A PSU test write-up says cracked solder joints on the regulators from thermal cycling are a recurring fault, and a unit sagging to 4.6-4.7V under load may not show symptoms until it fails. It adds that cheap switch-mode replacements can inject noise into video and audio on some C64 boards. Source
  • Tip: 9V line dropping points at the transformer (Low confidence). On the MIDIbox forum a poster says the most reported brick fault is the 9V line falling to 3-4V while 5V holds, which indicates a short in the transformer coils. Potted units are described as not serviceable, and aged diode rectifiers can raise the voltage delivered to the computer. Source
  • Story: Recap improved a grainy picture (Low confidence). A 250407 board restoration reports that replacing the electrolytics on the main board and RF modulator, watching polarity, improved a grainy washed-out picture, though the VIC-II stayed soft. The same job swapped MT-branded RAM for another make and added heatsinks. 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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