BOARD NO:     0058
GAME:         Turtle
MANUFACTURER: G.G.I. Corp.
DATE:         1981
HARNESS:      KONAMI-S

SYMPTOM (12/05/96)
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No sound.

SOLUTION
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Digital noise from the speakers suggested that the amp was outputing something. Using a pulse injector on a couple of the AY-3-8910 audio output pins produced tones at the speakers confirming that the analogue audio and amp sections were working properly. Looking at the sound Z80 pins with an oscilloscope indicated the processor was running, but it wasn't acknowledging it's interrupt or performing any write cycles or IO cycles. It looked as if the processor had crashed. Reseating the sound Z80 fixed the sound.