Off course if you'd done the tests in "correct" order you'd have saved yourself a few minutes, but ok that's enough of me being a smart arse
and I promise this the last time I'll mention this!
I'm not familiar with the Rottendog boards, but I'd guess the switch area is fairly similar to the originals. They probably use different row switching transistors to dump the 5W resistors and the predrive transistors (this is a fairly standard upgrade even for old driver boards), but the circuit behind this will probably be the same. If the chips are socketed you could try and swap a few around to sort out if the fault is chip or board / track related. The switch PIA and associated buffer chips are the ones I'd swap if I could. In the original WMS design they are IC10 the PIA, IC13 & IC14 the col buffers and IC19 & IC12 the row buffers. It's probable the buffers aren't socketed so you may not have that option.
Do you have a schematic for the board and can you post up a snippet showing this area?
