Cheers already did that one .Via the switch diagnostics, I found that there was an issue with Q42. This meant It didn't register the two balls in the troughs . I replaced the transistor. I actually played the game for an hour or so which was cool. Then in crapped itself again. Have not had a chance to look further but it would appear the transistor is fried again. Must be an intermittent short I think? I will work through the Switch matrix and see what I come up with .I dont think the game has been used for well over ten years so I expect to encounter a few issues. The other thing is the background music works but is really distorted. The voices seem ok. I did find that the -12v line was  around -16V . Got components to do up the power supply hope it will help.
Cheers