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

Related Pac-Man / Ms. Pac-Man Repair Cases

• Dead Board With BAD ROM 0 in Test Mode
• Static Garbage Screen Caused by Z80 Socket
• Screen Full of Zeros With Irregular Black Blocks
• Screen Full of Red 2s Caused by Loose Sync Bus Controller

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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