Sep 262015
 

Got this Sunset Riders PCB for a repair:

Sunset Riders_PCB

Gameplay and graphics were OK but music was accelerated and distorted:

Music is generated by the YM2151 sound synthesis chip widely used in many arcade systems:

YM2151

For first I checked its clock input pin and measured frequency was fine (3.579 MHz)  :

good_YM2151_clock

When I piggybacked a good chip on it correct music tempo was restored:

Replacing the chip fixed the issue completely.

 Posted by at 8:37 am