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Repair guide

Replace a failing Commodore 64 power brick

The original sealed C64 power brick is widely reported as a weak point, and a failing one is said to be able to feed the computer bad voltages. Replacing it with a modern unit made for the C64 protects the chips.

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Power · Easy · about 20 minutes. Worth doing. Reports say this fix helps on many machines.

You are in the right place if: The C64 shows no picture or garbage, or the original brick is hot, buzzing or suspect.

Before you start

  • Do not open the sealed power brick. The mains side holds dangerous voltage.
  • Do not use a generic adapter that is not specified for the C64.
  • Do not leave a suspect brick plugged in unattended.

Board revisions and models

Other Commodore machines (VIC-20, C128) use different power supplies. This guide is about the C64 and 64C only.

Parts you may need

  • Replacement C64 power supply. Made for the C64 Amazon · eBay

Tools

  • Multimeter. Measure low voltage side if needed Amazon · eBay

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Step by step

  1. Unplug the old brick Disconnect it from the wall and the computer.
  2. Look at it Inspect for cracks, burn marks or a strong smell. Do not open the sealed brick.
  3. Check what you need The C64 needs a low-voltage DC and an AC supply. Buy a replacement made for the C64 rather than a generic adapter.
  4. Fit the new supply Plug the new unit into the computer's power port first, then into the wall.
  5. Switch on and watch Check for a normal blue screen and READY prompt.
  6. Retire the old brick Do not reuse a suspect brick and dispose of it properly.

Tips, tales and maybes

Found in write-ups and forum threads. These are other people's reports, not tested by us.

  • Story (Medium confidence). A Commodore SX-64 keyboard restoration exposed a sagging 12V rail, a reminder that weak power can hide behind other symptoms. Source
  • Maybe (Low confidence). A failing brick can send too much voltage, so fit the new one before powering the computer again. General technique, no source.

Guides we used

We wrote the steps in our own words from these. They have the photos and the full detail, so please read them and support their authors.

Boards and models vary, so check what is in front of you. A repair can involve hot tools, chemicals and, on some machines, dangerous voltages. You do it at your own risk.

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