Quoted from eyeamred2u:
The wireform was slightly bent, breaking the opto, very weird.
Now I have MPF issue where SW 72 and 75 don't register. Brand new opto boards boards, very frustrated now. Going to check the main opto board tomorrow.
Pulling the MPF out and removing the opto carrier from it is the only way to work on it.
Put the game in switch test and plug the 12 pin connector in "live" under the playfield.
It wont blow anything up.
I hate this unit with a passion.
Faz's guide helps a lot but doesn't address aftermarket opto boards and how crappy they are.
Do you have original opto boards or gulf stream ones?
I have many times thought I had a bad opto.
However in fact the optos are so tricky and sensitive they only work well if they are perfectly aligned with their corresponding transmitter or reciever.
This is mostly impossible if the opto carrier is twisted, bent, crushed or mis-shapened in any way.
The piece of crap should have been made way more rigid or out of steel or aluminum.
Gentle nudges of the opto's can get them working if they are slightly out of alignment.
Twisting the opto board works well also.
This is accomplished by adding a layer if electrical tape or gorilla tape on one edge or the other of the opto carrier.
Sometimes along the whole length with an extra bit near an offending opto.
I have 2 or 3 layers of electrical tape across the receiver side to compensate for the incorrect led length.
This along with additional edge pieces to get it flat.
Still after a few days it warps and an opto starts acting up.
Solder lumps on the bottom of the opto board makes the board twist after its screwed down. Try to remove them if they are an issue.
Looking down the row of LEDs on either side, they should be straight across from each other.
Once this is accomplished it will work perfectly.
However after bolting it all together, it can change due to the installation itself.
Again, I hate this unit.