Beaky,
Thanks for the advice re the diodes on the flippers. Chucked in an new set tonight and machine hasn't failed since, its probably a bit early to say definitely fixed, but definitely looking good 

B.T.W. Just fired up the Countdown. Its been about 18 years since I played it, i rebuilt the electronics 3 years ago and never finished it off. Just put a rubber kit in it and played a few games.... Far out what a blast.