I have the same problem, no buttons work for the track pak (steering wheel and gas do work tho). And when i put the original working pcb back in the buttons are still broken!!!
this may help: http://www.thebasementarcade.com/index0809.htm
I'm out 3 of these 40 pin connectors with cable and dual-layer inserts. Came from Ivan Stewart Super Off Road arcade boards. What/where are the replacements? Specifically only the pins are broke so I could just replace that side... thanx dudes!