Commodore 64 Repair Bench Testing

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Lee from More Fun Fixing It sets up a full Commodore 64 repair session in his latest video. Surrounded by breadbin models and a handful of C64Cs, he lines up machines for assessment. This episode focuses on what he calls “repair triage,” where each computer is tested, cleaned, and checked before deciding if deeper repairs are required. The focus keyphrase for this piece is Commodore 64 repair bench.

The session begins with a promising C64 breadbin in decent shape. With sockets filled with CIAs, ROMs, and a sturdy PLA, the system powers on successfully. Aside from a dirty keyboard, this one is deemed a working machine. Moving on, Lee finds another C64C labeled “dodo,” assumed dead. Surprisingly, it powers up as well, suggesting his workshop environment—or possibly a questionable power supply—might have influenced earlier failures.

Not every unit is so forgiving. A third machine boots to a blue screen, hinting at RAM or CIA problems. Lee methodically swaps chips into his test board to confirm suspicions, only to find some parts still functional. The fourth machine proves trickier, showing intermittent results under diagnostics. Suspecting a failing ROM or PLA, he leaves it for a later deep repair. These moments highlight why the Commodore 64 repair bench approach matters: rapid testing narrows down where the real problems lie.

Later in the lineup, Lee encounters a case labeled “works but flickers.” Despite initial hope, unstable color output suggests a failing PLA or CIA. Another machine gives only a black screen, prompting oscilloscope checks for reset and clock signals. While activity is present, inconsistent address lines raise questions about multiple chips fighting on the bus.

The most challenging system is a rusted, spider-infested C64 that looks like a true shed find. After evicting the webs, Lee discovers correct voltages but an overheating PLA, confirming this one’s a serious candidate for future board work. With missing keys and cosmetic wear, this unit promises to be a longer project.

By the end, Lee has a mixed bag: some working systems, others needing new chips, and a few requiring significant board-level repairs. The video sets the stage for future episodes, where he’ll tackle the tougher cases one by one. Anyone fascinated by retro computing repairs will find the Commodore 64 repair bench process both practical and entertaining.

][avok
Tech Junkie, Pit Bull Rescuer & Advocate, Pizza Connoisseur, Brewer of Beer, Lover of Music, Gardener, Traveler, Strategy War Gamer, Veteran.
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