We have an IJ4 that once in a while, shooting an orbit, triggers end of ball. Flippers stop working, ball drops to the trough, and curses fly.
Digging more into it, we found that the right orbit spinner  is also_ triggering the indicator for trough jam . Both share the white-blue return line.
Triggering the optical trough jam sensor does not trigger anything else. Triggering the right orbit top  and bottom  also trigger nothing extra.
Disclaimer: I'm new here. But, in my mind, it seemed like perhaps focusing on the spinner  was in order. Disconnected it under the play field, then tested the diode with a multimeter. The diode check function reported near-0 values in both directions; whereas known good diodes were reporting 0.6 volt drops in one direction and no flow in the other. "Ah ha!"
Alas: swapping the diode for a fresh 1N4004 appeared to have no effect. I also confirmed that the orientation of the diode matched the original position, as well as matching the other microswitches on the field.
I'm reaching the limit of my n00bness, looking for advice. Am I misunderstanding the likely culprit in the switch matrix? Should I swap the opto board out on the trough jam ?
Below is the matrix for IJ4, with the two sensors highlighted where I'm seeing my problem.