Daniel re the sound board another check is as follows: on the CPU connector A1 J2 pin 24 is the reset line. This should (I think, once again I dont have a Rock schematic) go to the sound board at A6 P1 - pin 9. With the machine off do a continuity test between these two points. Also check the wire colouring on these too confirm I am right in my thinking I.e is it the same wire.
