Ok guys, Sat morning update...

With respect to the SDB, i have replaced the resistors and diodes corresponding to the bad transistors. The old diodes and resistors all checked out ok...replaced them anyway.

This morning i pulled out (desoldered) all the coils from the playfield, removed diodes, checked coil resistance and diode test, all parts check out OK. Replaced the diodes anyway. Knocked coil was fine, i wonder if the coils have been replaced, they look half decent....???

So this now leaves two possible options
1. Bad wiring, poor pin connections or a short somewhere, or
2. A bad Solenoid Driver Board.

I have a feeling its the SDB, i am tempted to swap in the rottendog and chance it....

Thoughts?