I got for repair a clean Spider-Man PCB set, actually a conversion on a donor Sega System 32 ROM board (motherboard was from Rad Rally) :
The board booted up and played fine but sound samples (FXs, speeches, etc...) were totally missing :
Looking at hardware the samples are handled by a surface mounted IC marked 'ASSP 5C105' :
The chip is actually a 'RF5C68A'in disguise, a PCM sound generator IC manufactured by Ricoh and used in Fujitsu's FM Towns computer series, along with Sega's System 18 /32 arcade system (sometimes you can find it marked as 'ASSP 5C68A' and Sega '315-5476').Datasheet is available so I looked at the pinout :
Pin 36 'SDLH' is the serial data output connected to pin 8 of the near Sanyo LC7881 DAC (for digital to analog conversion), probing this pin I found it stuck low all the time :
This was a clear sign the 'ASSP 5C105' was internally fault.Sure enough I removed it with my hot air station :
I took a spare from a dead System32 motherboad and installed it :
This restored all sound samples and fixed board completely.Job done.
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