torture machine

[rustyspurs]

hi, i have a maygay stepping stones machine that will not power up, i have tried everything i can and have run out of ideas so any advice welcome.
so far i have replaced all the boards, proms and powersupply, and it has made no difference.
i can hear a faint alarm which sounds in time with the flashing red light beside the keyhole on the outside of the machine.
on the main board three lights dont light
ld1-security
ld2-reset
ld6- +vdisp
all the other boards are lighting as are all the lights on the power supply but there is no sign of power to the outside display.
i bought the boards from eggy777 of ebay( after advice from you guys) and they have been great in trying to solve the problem (3 weeks of sending boards back and forth), they even had these boards running on a machine the same age as mine.
so if its not the boards or the powersupply what can it be??

thanks in advance
Paul

[Reel King]

the only thing it can be...

..wiring.

might be time to dig out a multimeter and do continuity testing..