Jun 242015
 

The game was working fine but you could hear only the sound fx, not the music.

Usually these kind of issues are related to either the DAC or the operational amplifier connected to the FM sound chip.

I used my external amplifier to probe the output of an operation amplifier and I could hear perfectly the music.

After checking for interrupted lines I noticed a missing cap.

Bridging the two pins restored the music.

Easy job!

Foto 15-05-15 18 02 59

 

Foto 15-05-15 18 02 49