Missing Background Siren and Hum With Aftermarket Ms. Pac-Man Daughter Card

Repair Case Summary

This page documents a firsthand Missing Background Siren and Hum With Aftermarket Ms. Pac-Man Daughter Card repair case. It is intended for technicians and collectors troubleshooting original Pac-Man or Ms. Pac-Man arcade PCB hardware.

• Date: 2018-06-09
• Board: Original Pac-Man PCB with aftermarket Ms. Pac-Man daughter card
• Category: Sound / ROMs / daughter card
• Symptoms:
  • Ms. Pac-Man booted and played but background sounds were missing.
  • C49 was visibly missing.
  • With the daughter card removed and the board run as Pac-Man, background sirens were present but a humming noise remained while the custom 6F ROM was installed.
• Diagnostic observations / tests:
  • Replacing C49 alone made no difference.
  • The aftermarket daughter card used custom-burned ROMs, and 6F also contained a custom ROM.
  • The board was cleaned and custom ROMs were replaced with factory units; the hum disappeared.
• Components / locations investigated: C49, 6F, aftermarket Ms. Pac-Man daughter card, custom ROMs
• Root cause: Problem associated with custom-burned ROMs, with C49 also missing.
• Repair: Removed the custom-burned ROMs, restored factory ROMs, and replaced C49.
• Result: All sound issues were resolved.
• Search terms: Ms Pac-Man missing siren; background sound missing; hum; aftermarket daughter card; custom ROM; 6F; C49
• Evidence: Physically verified repair / firsthand repair log

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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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