Hi Pete,
can you check with your scope the signals on pin 13,12,3 and 4 of IC 9 to see if there is any noise present when pressing BREAK?
Maybe IC9 is bad.
For testing, you can remove IC1 (6522) or IC25 (8255) to see if one of these IC's create noise on the line.
Only the 8255, 6502 and 6522 are connected to the Reset signal or do you have some external boards connected?
Greetings
Kees
can you check with your scope the signals on pin 13,12,3 and 4 of IC 9 to see if there is any noise present when pressing BREAK?
Maybe IC9 is bad.
For testing, you can remove IC1 (6522) or IC25 (8255) to see if one of these IC's create noise on the line.
Only the 8255, 6502 and 6522 are connected to the Reset signal or do you have some external boards connected?
Greetings
Kees
Statistics: Posted by oss003 — Mon May 06, 2024 8:33 pm