Some LEDs interfere with Optos. First I'd try removing the LED and see if the optos return to working normally.
thanks nino will do some more experimenting,have noticed that if i move the opto board back it triggers the magnet so maybe my fat fingers bent the bloody thing out of alignment
or it is simply the you beaut led making it play up,plus there are a couple of posts that only half screw into the wood putty and sit at an angle.so process of elimination starting with the led
Ben you have my problems, adjust the coin mech and find the CPU blows 
. I have a similar problem with my Theatre of Magic. I replaced the ROM's and now the ball save option doesn't work if after hitting the trunk the ball goes SDTM. Put the old ROM's back and still the problem. My problem does effect game play like yours does. Good luck I'm sure you'll get there.
Yes pinball god the probs you have sound like the type of thing that could only happen to me
