The 5 switch opto unit gave me a lot of touble, but its solid now.
I have the replacement led boards in it.
The reciever side LEDs are too long.
They hit the e-clips on the interrupters and cause the stitches to stick down.
I added 1/16" nylon washers under the mounting screws on reciever (dark) side only and it works to solve the interference issue.
I bought the 3d printed insert to do a professional job on this.
Dont buy it! The led holes dont line up and it's not drilled for the screw holes. I drilled it out for a better fit but with it installed you cant adjust the opto angles.
And this is super important!
It's a great idea but very difficult or impossible to implement.
Led alignment is super important or the opto stays enabled and you cant break the beam.
With the stock original you can slightly bend the optos to get them all to work while its plugged into the game. Then wrap it up for installation onto the MPF.
It's not even an issue of the LEDs being perfectly straight or aligned to each other. The reciever just has to hide behind the interrupter cleanly.
Too much errant light from the opposing transmitter will lock it on.
Adding the washers to receiver board makes it way thicker.
This along with paper and tape makes it even more thicker.
This causes the scoop to crush it when you bolt it down, throwing off your opto alignments.
Adding washers under the feet of the scoop assembly solves this.
Optos switches are now flawless, and using the homepin replacement board.
In fact all optos in the game work petfectly.