I picked up a JD a couple of months ago and I noticed it sometimes has one to many balls for multiball. I know this is a common problem with the trough opto so I tried to order a new opto board from Great Lakes Modular. I sent them an email stating what I wanted to buy and to let me know how to purchase the item. This was about 2 weeks ago and I havn't heard anything. Does anyone know how I can order their opto board for this game. Thank in advance.

Thank you I appreciate the response. I’ll put a wanted ad up for the part then buy from pinballlife.

Mine did the same thing during multiball regardless of entering through ramp or playfield. I updated the ROM to L-7 (not positive on the number, but whatever the latest is, I believe it is L-7) and everything worked as it should. I think I bought it from Matt's Basement.

I also had trough issues (always one extra ball during multiball, starting super game with 3 balls instead of 2). I had to bite the bullet and pick up new trough opto boards.

The other thing I noticed and I know it has been mentioned here, but there is a two prong female connector in the backbox that looks like it connects to a 2 prong male on the boards. This is located towards the bottom right of the boards, I forget the number on the board. If you push the connector onto the board a bunch of funky things happen. The insert lights do not light as they should. I made this mistake as it definitely looks like it should be connected.