Working on the CPU of a Star Wars DE. Have it set up on the bench with +5v and GND and I get all three LEDs (Blanking, 5v & PIA) lit and staying lit.
I've read somewhere that this means one of the PIAs is bad.
What I don't understand is whether I use Leon's Test EPROM, the Star Wars EPROM or just no EPROM at all, there's no difference over the board. This is why I think the CPU isn't loading the EPROM. I've checked all the connections from the schematic between the CPU, the address buffers and the EPROM and there's continuity everywhere it should be.
I'm guessing one of the smaller chips might be the cause. Is there a way to check if a chip is malfunctioning without removing it from the board?