While playing last night, as the last of ball 2's multiballs drained the ball didn't end. Then, ball search.
All 4 balls were in the trough.
Poking around revealed many switches not registering. The entire switch matrix row 2 is out.
Tron Legacy-Switch Matrix-Pro, p49 (resized).PNG
A multimeter probing reveals nice continuity from the end of the line SW32 Bottom Bumper all the way up to J1P3 pin & the neighboring SMT reisstor on the CPU PCB, so no broken wiring to blame.
Tron Legacy-CPU Layout, p110 (resized).PNG
Probing a little further in, game power off, the measurements at the resistor test point, capacitor test point, & the closest leg of the transistor seem to match the same set of probed items on the Q1 row 1 set of components. So, assumption that R2, C2, & associated traces are OK.
Suspected culprit: Q2 transistor. Thankfully, it's thru-hole, so easy removal & replacement.
Tron Legacy Switch Matrix Transistor (resized).PNG
Is there a good way to test it, perhaps by probing J1P3 with logic probe? Should I be seeing ultrafast flickering at 5V on this pin? Or probe it & a neighboring pin & see if they resemble each other subjectively? My ancient multimeter probably won't be of any use here.
If Q2 is indeed the culprit, recommended to swap all of its neighbors when I swap Q2, under the assumption that they all might tend to go together based on being in a similar batch, similar usage, etc.? Or better to let these lie & address only as needed?
Thanks in advance for any help.