Can some kind pinhead post a few up close pics of the two small opto boards and the surrounding wiring on their RBION? I just picked one up a few days ago (along with a LOTR) and it's my first Stern game that I need to troubleshoot. So I understand that the optos work differently than BW and I've read Sterns service bulletin 67 on their optos but I am stuck.

Here's the deal. The shrunken head, idol and super jackpot optos are all not working. In switch test most they all show as closed. From what I read they should all read open. The idol opto transmitter is on and red, but not the other two transmitters. I get 5V at all the transmitter 2 pin sets. I have swapped in new LEDs in the idol to test, but that didn't change anything. Didn't think it would since the switch is reading as closed anyway and it sure would be odd that all of them are bad.

When I pull the main connector from the opto board the switches will read as open and then they will register a hit and close and stay closed when I plug it back in. All the three optos are on the same column in the SM, but the other switches in that column work fine. Could I have a bad transistor at Q3? How do I test that? Could I have a ground short somewhere, even though the non opto switches in that column work fine?

One other question. When replacing the opto LEDs, does the positive (the long side, right?) go in the K or A side of the opto board?

Thanks in advance for any help!

Thanks for the pics!

My concern was that the three optos all had speaker wire on them, which I assumed was not factory. Especially since Stern did not use speaker wire any where else - not even for the speakers. Lol.

My other concern was the transmitter for the idol opto, as the speaker wire from the opto does not run to the board, but to some other wire which then runs to the transmitter pins on the board. Well, now I know that's not the problem.

Anyone got any ideas then why all three of those optos register closed, but every thing else on that column is fine? I've tried replacing the optos to no avail...

I replaced them with the Stern transceivers, not the old BW transmitter/reciever ones. Just replaced the opto bulbs themselves, not the miniboards and wires. I think I'll just go the expensive route and order two new opto boards and wiring with the transceiver boards.

I just don't believe that's the problem. Hard to believe both opto boards are bad...

Hey ryan1234, what problem did you have that necessitated the board replacement? Was your optos registering as closed all the time as well?

Thanks for the help. I did reflow solder on the idol opto and that did not do it. I'll report back after I get the new boards in.

One other question. The upper right flipper is weak as all get out. I've heard folks replace it with a stronger coil. Which coil? I don't want to get one that's too strong, obviously.

Ok, so I bought all new boards but that didn't do. Then, I got a pm from jsalce here on pinside who was having the same problem. He figured it out though - there is one wire running to the head which runs all the optos. Apparently, the wire is a bit short which results in the connector in the head coming unconnected when you put the head down. I found the connector in the head and plugged them back together and...all the optos now work. Thanks jsalce!