Just taking a stab in the dark here, but check the 3amp slow blow fuse on the power supply board for the solenoids - if it's blown the Darlignton on the driver board has failed (Q71 i think) causing the coil in the outhole is stay on and blow the fuse. Replace the fuse and re-power it back up listening carefully for any clunks the moment you turn it on - if it does turn it straight off or it will just blow the fuse again. pull the fuse for that coil out from the fuse rack in top left corner of the back box and see if it will boot up ( i can't remember which one it is, so you may need to pull em all and refit one by one) - i usually replace these with 1.5a fuses while fault finding
