I've got a mistreated RoadShow pinball, it really needs lots of love and time, and Im doing my best.
I've checked and repaired all the connectors on backbox boards and playfield boards (optos) and that solved many problems.
Now Im stuck with a matrix problem, all 10s and 20s switches are not responding but the wiring is OK.
I've found an old ULN2803 drop inside the backbox so I suppose they tried to solve that problem changing the U20.
Following your nice forum and the Williams repair guide and did many test, and PUT A NEW ULN2803 on the U20 socket today.
Switch Level Tests
Before the new U20 the test said, ROW 1 GND SHORT and the ROW 3 and 4 did not respond, pressing START also says GND SHORT.
After the new U20, the test says that I have no more GND SHORTS, but switches from 10 to 30 did not respond 31 to 80s are OK, pressing START does nothing, not response at the Matrix.
WIRE JUMPER TEST
Disconnected J212, J206, J208, J207, J209, only left J205 (coindoor test buttons) connected at matrix side of the CPU board, so no coneection with the playfield.
Connected a wire to PIN 1 at J209 and at the other side of the wire Im using a diode.
With the diode I touch all the pins on the J207 on by one and check at the Switch Levels screen:
PIN 1 and PIN 2 do nothing, the rest of PINS register a good closed switch signal, 31,41,51,61,71,81.
Just for fun I did the reverse test, connected the wire to PIN 1 at J207 and with the other side of the cable and the diode (switched diode side), I touch all the pins at J209 one by one, 0 response, I suppose that this is logical but I have to try
Sooooo, guys, what should I do next???