Could it be the speed of the Eprom's you have not being fast enough? I assume your programmed Roms are verifying correctly once programmed, have you tried with a shorter ribbon cable on your adapter.
Hi there,
I know this is a year old thread, but I don't suppose you ever tracked down a set of schematics for this PCB? I'm currently repairing one and it has a few faults left and the schemes would make life so much easier!
Cheers, Mart.