Another board from the recent operator raid, an original Michael Jackson’s MoonWalker (on Sega System 18 hardware)
Despite its age and the use of the FD1094 CPU module with battery backed-up RAM the board was still working except for the sound samples (drums, speeches, etc..), they were missing or replaced by random ones:
The hardware uses a rebranded Ricoh RF5C68 as PCM sound chip :
Not able to find any datasheet I went to “listen” its pins with an audio probe.When I hit the analog outputs (the IC has an on-board DAC) I realized that sound came already wrong out of it.So the chip was the only responsible and it needed to be replaced:
Done and…success!Board completely fixed.