Does anyone know these cards ?
I've got one here trying to make it work. I've reflowed the little extra board that had bad solder joints, and one of the chips needed replacement.
When inseretd in an apple II, all according to the documentation ; the computer boots as usual. When trying to activate it with PR#? (I don't remember the number now) nothing special happens
I don't see a picture and I don't see a signal at the oscilloscope
This is difficult to debug because it's nearly impossible to probe when inserted in a A2
The big black resistor (lower left) seem to be hot to the touch which I find weird.
Apart from the carpet bombing approach of desoldering ALL 20+ ttl logic chips, putting them all on sockets, and testing them all, I don't see how I could debug this thing.
Is it common ? I mean is it worth the trouble ?