hmm, kind of a stand still here and trying to get this machine playing. currently all optos are getting 12 volts and all transmitters are working (checked beam with cell phone).
I am getting row 6 ground error (white/blue J209-7, U19-9). this includes switches L drop score (only opto I can't seem to register in switch mode), top 3 lane middle target, left return, oto crypt popper (which register in switch test), left 3 bank top target, and middle 3 bank target left.
Here is what I find, I get 12 volt at J209, I get 12 volt at 10 opto board as well.
what's interesting is when I pull the power connector from J209 to the 10 opto board, all row 6 errors are resolved (on matrix grid), and the rollover switches in row 6 now work.
It seems as if the resistors (R1-7, and R25, 28, and 31) run VERY hot, so hot that you can feel the heat on top of the PF after only 5-10 mins of being powered up. I have a new 10 opto board on the way (2 months out), and was considering replacing all 10 resistors on the 10 opto board to see if this would resolve this issue? The resistors are rated at 220 ohms, 2W, 1/2W.
I have replaced optos (transmitters and receivers) as necessary, and fixed some pinched wires and cold solders as well throughout the machine.
edit, I have inspected all switches in this row/matrix, and can't find anything shorting.
Any suggestions would be greatly appreciated.