This is part of the e-mail, I have sent Barry today:
the fault is not on my board, because neither on the old board, nor my board the optos work, same as the GI-LEDs.
You somewhere have a conneector problem or a wiring problem under the playfield or a burnt GI-fuse.
So first we should get the four great GI-LEDs running.
Please post fotos of your power driver board (PDB) connectors J115, J120 + J121. The GI for the clock-LEDs are at connectors J120-9 (white-yellow) and J121-3 (yellow).
BUT first check Fuse F108 (this one is responsible for the GI-string 3) on your power driver board.
Would also be a good idea, to check the other GI-Fuses F106, 107, 109 + 110.
Please report, if the fuse F108 is OK.
You should also follow the yellow and white-yellow wires from the right connector at the clock backwards to the PDB and look, if there is a connector under the playfield somewhere, that has a bad connection.
When we have the 4 big LEDs working, we will go to the optos, OK?
- Ingo ..."
First we should solve the GI-Problem, then we will see, where the fault is in the wiring for the optos.