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Garbled Static Graphics, No Boot, No Reset, Plus Loud Hum
Repair Case Summary
This page documents a firsthand Garbled Static Graphics, No Boot, No Reset, Plus Loud Hum repair case.
It is intended for technicians and collectors troubleshooting original Pac-Man or Ms. Pac-Man arcade PCB hardware.
- Date: 2018-06-06
- Board: Original Pac-Man PCB
- Category: Boot failure / ROM sockets / sound hum
- Symptoms:
- Garbled static graphics on screen.
- Board would not boot.
- No reset.
- ABC Diagnostics booted successfully.
- A loud hum was present through the speakers.
- Diagnostic observations / tests:
- Installing ABC Diagnostics requires removing ROMs 6E-6J; because diagnostics booted, one or more ROM sockets were suspected.
- Diagnostics otherwise passed.
- After all four 6E-6J sockets were replaced, the board booted and played normally.
- Further inspection found capacitor C50 missing.
- Components / locations investigated: 6E, 6F, 6H, 6J, ROM sockets, C50
- Root cause: Bad ROM socket connection(s) in 6E-6J and missing capacitor C50.
- Repair: Replaced all four ROM sockets at 6E-6J and installed the missing C50.
- Result: The board booted and played perfectly; the speaker hum disappeared.
- Search terms: Pac-Man garbled static; no boot; no reset; ABC Diagnostics boots; ROM sockets; 6E; 6F; 6H; 6J; C50; speaker hum
- Evidence: Physically verified repair / firsthand repair log
How to Use This Repair Record
This is a firsthand physical repair case. The same symptom on another Pac-Man or Ms. Pac-Man PCB can have a different electrical cause. Use the documented diagnostic observations and tests to guide troubleshooting rather than replacing a component solely because it repaired this board.
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