In the latest video from the More Fun Fixing It YouTube channel, it’s time for a Commodore 64 CIA chip replacement. This is the same machine that appeared in a couple of earlier episodes—first suffering from a spectacular capacitor failure. That issue was resolved, but of course, when it comes to old hardware, one fix often leads to another.
After repairing the blown capacitor, the next step was to run a full diagnostic. The test flagged a faulty U2 CIA chip—one of the two Complex Interface Adapters responsible for managing input devices, timing, and other system functions. When a CIA chip goes bad, things like the keyboard, joystick, or timers can stop responding entirely.
This video covers the Commodore 64 CIA chip replacement from start to finish. Viewers get a clear walkthrough of the removal and installation process, along with helpful tips and observations along the way. As always, the channel delivers a calm, approachable explanation of the repair—making it a great watch whether you’re troubleshooting your own C64 or just curious about the process.
