High? I just know that CTS trace was ok from U305's pin4 to COM's pin5.
I was changed U304 before but didn't help. Should I replace U305 it too?
Injecting a pulse? I was checked the traces between Paula/CIA U301/U304/U305/COM and they were fine except what I wrote in the first post.
Sorry didn't read the first thread. (That's Me...). I just remember once doing a whole lot of troubleshooting on a serial port and cable just to find out one of the pins/sockets(cant remember which) had recessed itself (had been pushed back in the plug/socket) and was not connecting. I'm guessing you have a breakout box and have tested the continuity of each necessary line to the back of the serial socket in the 2000? You do have a multi-meter or continuity checker? When you say "checked the traces", what does that mean?
Just an aside: I think I found an error. The schematics you posted refer to the "Infernal" serial port. That one's always going to cause problems.
Keep up the trouble shooting.
