T2 left flipper fixed

I was having some problems with the left flipper on T2, ever since I switched the power driver board from BoP. The flipper worked (as in, it was moving), but the machine didn't register that it was pressed. That lead to problems during video mode (the crosshatch could only move right) and when entering initials.

Clay's great guide had this advice:

Pre-Fliptronics WPC game's lane change doesn't work. This is almost
always driver board chips U7 (left flipper) or U8 (right flipper)
which are the 4n25 opto isolators.

My local supplier had two different 4N25 opto isolators. At least the part numbers were different, so I ordered two of each.
After removing the power driver board, I noticed much to my surprise that the resistor connected to U7 had come loose!



Even though inserting and removing the board is a strain on the molex connectors, I took a chance on just soldering the resistor back on and put the board back into the game without swapping out the opto isolator.
Success! Everything is working like it should now! At least that's what the switch test said. I never got to video mode, and got even less close to entering my initials...