Thanks, i did find them on the wiki, is this pic the ones?
Also had this to say about power filtering;
System 9 MPU Williams used a single version of the System 9 MPU in all System 9 games. A few minor modifications to the board may have been made, but it's essentially the same board for the entire 3 game run of Space Shuttle, Sorcerer, and Comet. The picture at left shows an early board that featured two inductors (copper wound coils that "smooth" DC power) at L1 and L2, adjacent to connector 1J17. Later revisions of the board used "zero ohm" jumpers instead, presumably to reduce cost.
Anything there i should get him to check out?