It's good that you got it going. Would be interesting to know what sort of testing Rottendog do prior to shipping, did they make any comments on this?
The thing I can think of that _might_ cause this chip to fail is a solenoid voltage being introduced to the switch matrix. (It would also be reasonable to think the chip _might_ survive this and that is part of it's roll so it may well have been dead from day one) The solenoid voltage finding its way to the switch matrix would probably be due to faulty play field wiring and if still present could cause the same failure - I'd be looking very hard around this area. Keep in mind it may be intermittent and caused by some movement or action on the pf.
Out of interest do they give you a schematic with the board? What chip do they use to buffer the switch matrix reads?
