I understand a bit more now, thanks.
Might have to get out my sys 11c board from Dr Dude again and have a look at the chip as it had a U25 ram failure and just locked up. So I bought a new rotten dog board and had issues with that too!
On my Space Station I took out heaps of 6821 PIA,s along with transistors and micro drivers in a catastrophic fail, still don't really know how I did it though? Lucky I guess
