Just got bit by the Pinball bug and bought two machines a working JD and TMBOP with issues. When I turn the TMBOP on it give me a Pinball Missing error message and it will not function, meaning flippers wont function and a ball wont load.
I opened it up and put it on test mode, and most of the switches do not work, ball troughs, lanes, etc... I check the associated fuse and they seem fine (pulled them and used my multimeter). I then look at the WPC CPU board since the machine tells me the wires are on J207 and J209. Go figure, J209 is unplugged but I don't even see a cable for it. What I do see is a J208 labeled cable connected to J208. J206 is also not plugged (I don't see the cables). So 207 and 208 are plugged in and 206 and 209 are not plugged. To further complicate things, the batteries are unplugged, and it seems they have leaked. One of the posts on B3 have broken off. It seems the liquids have dripped on the R31-R34 as well as on U19 which from what I can tell is relevant to the switches.
I have attached a picture and a link to the WPC schematics.
Looks like since I have been here less than 2 days I can not post the schematic. If you copy the below into google you will find the chart.