Can you post a picture of the wiring at the MPF motor? The red wire should be soldered to the tab with the red dot next to it.

There are 2 Allen screws to tighten behind the POA playfield. Check them both.

Don't quite understand this. Can you post a picture or video to help us understand?

Do both upper and lower flipper buttons on both sides register in switch test? Best if you open the coin door so the flippers do not register the EOS switchss as it makes it tough to notice the flipper buttons registering.

Forget the test you are running and exit out of it. Go to the switch edge test and press the flipper buttons. Left flipper button should register left upper and lower flipper button switches and the right flipper button should register the right upper and lower flipper button switches. Do this test with the coin door open so the flippers do not activate.

I suspect the left upper flipper button opto is not registering in the switch test, which would be what controls the mini playfield to tilt to the left. You may get lucky and just cleaning them will get it working. Chance though the opto has failed.

The mini playfield starts off in the level position? I have my game on loan so I really can't dig too much until I can get in front of it again.

Can you post a picture of your MPU board? Hopefully you do not have any battery corrosion on the board.

We are referring to the flipper opto board inside the cabinet attached behind the flipper button. As mschonbrun suggested, swap the left and right flipper opto boards. Two wood screws should be holding the board in place against the cabinet.

Yes, he would have been able to use the left flipper with no issues. Since this is only a 2 flipper game, the "upper" flipper button optos are used to enter your name for high scores and for controlling left/right movement of the mini playfield.