Did you ever find the solution?

My LOTR is doing this too. But on the right flipper. The flipper Initially started dropping during gameplay then stoped working completely. I lifted the playfield to find the plastic plate on the coil had snapped and the diode had lifted off on one leg.

I replaced the diode, but when I turned it on the flipper didn’t work. The original issue
Blew the fuse.

when fuse was replaced I turned the machine on and the flipper locked on.

Transistor was fried. So changed the transistor. Turned it back on. Flipper didn’t jump up (Yay!). Started a game flipper worked and the second time I hit the flipper button the fuse blew.

Replaced the fuse and the flipper jumped up again! Board out, replaced the transistor again.

So I have been through several fuses, transistors and diodes.

I’m waiting for a new coil to arrive in the post so I can put that in and eliminate the coil as a cause. I note in your post that you tried a new coil and that didn’t fix it for you. I hope you found the problem,

I've just put in a new coil - same issue.

Game starts up but as soon as I press the right flipper button the right flipper locks on - blows the transistor, then the fuse goes.

I've changed the flipper button switch - same issue

I have not changed the end of stroke switch yet

I've followed @Pin_Guy's advice about checking grounds between the flipper coil and ground - There is continuity between the coil and ground, however when I unplug from the board and test it there is not. Testing the pin it connects to = ground.

So new transistor in again - this is the 5th time I have changed it now.

rechecked the coil - no longer grounded.

interestingly neither of the flipper coils show continuity with ground when I close the switch at the flipper buttons. Are they supposed to?

Anyone have any other suggestions what to look for next? running out of Ideas and assuming now it is most likely a board issue.

I solved my problem.

In trouble shooting, I replaced the coil, diode, EOS, cabinet switch. But no change. And in doing this worked my way through 5 transistors and fuses.

That was enough for me, I I took it to a tech, who replaced the IO chip, and it’s working now.

So the initial problem was the diode breaking at the coil, but this obviously damaged the io chip.