I've now cleaned the corrosion, replace the 6809 socket and socketed the 7414 and replaced the parts around it. I then put it back in the machine. It booted and reported it had done factory reset (no batteries so no surprise there). After 30 seconds it started resetting repeatedly and then died. I've now got a dead CPU board even though I am sure that everything was correct. Guess I'll leave it until tomorrow now as I'll have to rig up a bench supply for it. Does anyone know if just supplying 5V will allow the processor to run?
Mike.