found the actual start relay
there was a misadjusted switch
i've adjusted it and now i'm getting a slightly different start up sequence
now when i plug it i've got a buzzing coil (spielend 'playing' relay) if i manually switch the start relay or press the left flipper it goes off,
when i press the left flipper the GI turns on & score motor turns, when i press start the ball gets kicked out and the machine tilts

after i've manually fixed the tilt relay, targets and rollovers activate the correct relays and score motor turns but no scores register on the reels and player/ball doesn't advance

i've had kids around all day and this is the first chance i've had to look at the pinny, it's my therapy  
it will be sleep time soon though ;)