In a hands-on tutorial from the Chicken 64 YouTube channel, viewers follow a thorough Commodore 1541 repair from diagnosis to game loading success. What starts as a non-responsive drive—stuck with its LED and motor always on—quickly turns into a deep dive into faulty reset circuits, bad logic chips, and the telltale signs of failing VIA components.
The Commodore 1541 repair begins with the classic red LED that refuses to go out. The culprit? A broken reset signal. This reset line is critical—it ensures that the 1541’s CPU and support chips boot properly. The video compares the signal behavior between a working drive and the malfunctioning one. Unsurprisingly, the broken unit’s reset line remains low, indicating a hardware fault.
Diagnosing the Reset Circuit
The host zeroes in on three small logic chips responsible for handling the reset line. The first chip, a 74LS14 inverter, fails to produce expected outputs—several pins sit in electrical limbo. This chip is replaced after socketing, and the LED finally turns off. One small win.
Next up is UB1, another inverter (this time a 7406). Once replaced, the motor stops spinning, but the drive still fails to communicate with a C64. That leads to the final suspect: the 6522 VIA. This crucial chip handles communication between the drive and the computer.
Solving Communication Failure
Scope readings of the ATTENTION signal show stuck logic levels when interacting with the C64. A side-by-side comparison with a working drive confirms that the 6522 VIA is dead. A quick swap breathes life back into the drive—error blinks signal that the drive is finally talking to the Commodore 64 again.
Final Touches: Speed and Alignment
But Chicken 64 doesn’t stop there. To wrap up the Commodore 1541 repair, the video walks through head cleaning, rail lubrication, spindle speed adjustment using a smartphone screen strobe, and head alignment using diagnostic software. It’s a masterclass in vintage hardware TLC.
The payoff? A successful game load on a real C64, complete with the assistance of a junior tech apprentice.
Summary
This video offers a practical and engaging look into repairing a Commodore 1541. From identifying logic failures to fine-tuning alignment, every step is clearly explained with oscilloscope readings, chip replacement, and diagnostic insight. Whether you’re troubleshooting your own drive or just love retro hardware restoration, this is an episode worth watching.
