I'm trying to diagnose a switch matrix issue on my Special Force. There are three targets that when closed trigger other switches. They are the R, O, and C in the ROCKET targets. When the R is closed, in game and in switch diagnostics, it triggers the B target in Bomb and the right coin door. If you look at the switch matrix, they are all in the same row. See picture.
Special Force Switch Matrix (1).png
I've circled the switch that I closed (in red) and showed the other two switches that register at the same time. Bomb "B" registers all the time when "R" is closed. Coin right sometimes registers. In game, the left bumper also sometimes registers, but rarely does this in switch test mode. A similar thing happens in switch test mode when I close Rocket "O", only this time Bomb "O" and Coin Left register as closed. So, essentially, move the circle and two arrows down one row but keep in the same columns. And, a similar thing happens when I close Rocket "C", one more row down.
A few other things to note. It doesn't matter if the trough switches are closed or open -- the same thing happens. No other switches are closed when this happens. If I close the Bomb switches (column with the right most green arrow), only that switch registers, not the others. Same with the coin door switches. So, it is only the Rocket "R", "O" and "C" switches that cause this problem, and the problem seems confined to their row.
At first, I thought it was a leaky diode, but looking at the matrix, I don't see how that could be given the symptoms.
Any ideas? Thanks in advance!