Update on the strange opto issue with my TZ

>My TZ has a strange opto problem that I just can't figure out what's
>causing it. Whenever the left flipper button is pressed all the way
>in, the right magnet opto (sw #81) always registers and the opto
>sometimes registers when the right flipper button is pressed all the
>way in. The opto doesn't register when the left flipper button is
>pressed such that only the lower left flipper is activated. IIRC, the
>opto will also register occasionally when the same thing is done with
>the right flipper.
>
>I've checked the custom opto board that's in the game (even put it in
>another TZ) and it's good. I've replaced the opto (both the
>transmitter and the receiver) itself first (as I originally thought
>the opto was going bad), but that didn't help.
>
>
>All of this was happening with my own power driver board (which needed
>to be serviced) in the game and a borrowed power driver board from
>Paul Drabik. Paul gave me another (working) board to try (this board
>is from CFTBL), but with this board in the game, the original problem
>remains and the 4 magnets in the game and the left ramp diverter now
>don't work (F103 is good) either in test or game play. The board in
>the game is the only one I have available for now.
>
>
>Paul and I looked at the problem before the CFTBL power driver board
>was put into the game and Paul had an idea that it could be a power
>draw issue whereby activating the flippers could draw power from the
>right magnet opto thereby causing it to register. We don't know where
>to look now for the cause of this problem (and I'm not sure why the 4
>magnets and the left ramp diverter now don't work). Any help would be
>appreciated. Thanks,
>
The magnets and left ramp diverter issues were easily fixed. I had
simply forgotten to plug in a connector on the power driver board.

I think I narrowed down what may be the cause of the opto problem on
the TZ. It looks like something is screwy with the 12 V circut. I
noticed that the opto registers (in test) when the clock motor is
running (which needs the 12 V to work) and the optos have been
disconnected at the same time. Unfortunately, I can't read a schematic
well enough to possibly determine what to look at next. Maybe there
is some kind of power leakage that leads to that particular opto
whenever the 12 V is activated (such as when the clock motor is
running or when I activate a flipper)?

Koi