Crystal Lake, IL
Quoted from barakandl:Rows (i blelieve) go CPU -> PIA -> NOT Gate (7404?) -> pre transistor -> main transistor
The cpu is good because it is booting up.
I would stick a logic probe on the PIA gate, make sure it is pulsing. Then look at the TTL gate output, make sure it is pulsing. Compare to other rows and replace part that is bad. If it is pulsing up to the pre drive base, replace both pre transistor and main transistor.
This! I was just working/fooled on a system 9 and it was the same type of issue. Replacing both transistors was the solution!
