I'm putting my STTNG back together after "restoring" it. I'm having an issue with the lower right flipper not working when the right flipper button is pressed. The left flipper and upper right flipper work fine. The lower right flipper switch registers as working in the diagnostics as well as the EOS switch. I checked for power on the right flipper coil lugs and I have 51 volts on all three lugs like the left flipper coil. I also did the following per the pinrepair guides and the right flipper did work:
"With the game on and coin door closed, use an alligator clip and attach one end to ground. Now momentarily touch each metal tab of the Fliptronics' TIP102 transistors (*not* the TIP36). You should see a flipper react"

I have also reseated all connectors and ribbon cables and that didn't help either. What should I do next?

Thanks for the suggestions on what to do. I will check the continuity of the transistor after work tonight. If I have to replace the TIP102 and TIP36 transistors for the lower right flipper (I think it is Q4 and Q12 if I remember from the manual), how do I know which corresponding 1N4004 and 2N5401 diodes to replace as well?

Ok, continuity is good between transistor tab and connector. 51 volts at the connector (orange-green wire). Press flipper button, zero volts.

Also if I press the lower right flipper button just enough to activate the lower right flipper switch I hear a hum from the coil. Also if I hold the lower right flipper up manually and then press the flipper button, the flipper will stay up until I release the flipper button.

I did that last night also. Clipped a jumper wire to ground and touched the other end of the jumper to the middle coil lug, flipper fired.

I'll test the resistance of the coil tonight also

I'm going to check to make sure I put the right wires on the right lugs - you may be right, that could be the problem. I'll double check the manual to make sure.

All the wires are correct on the coil lugs. The middle lug does not go to zero when the flipper button is pressed. The middle lug does not go to zero on the good working left flipper either. The power does go to zero on the "power" lug (orange green wire). The same on the left working flipper power lug

Also the problem is for sure with the flipper board. I put the fliptronics board from my fishtales in the star trek and it the flipper worked fine.

Found it!!!!! I traced lower right flipper hold circuit to the U2 chip. Found a BROKE trace between R35 and U2. Soldered on a jumper, checked continuity, installed the board, all flippers work. Awesome feeling let me tell you.