That's good. I'm also worried, though, about your readings of 11v and 15v for the 5 & 12v power rails. In particular, the mention of checking dc voltages with 'dc current' selected on the meter. If it's a typo, then something's wrong with the power circuits. If the meter was set to measure current, connecting it to measure voltage could've damaged the meter*, and wouldn't give accurate readings.
And there are two 12v rails used in this board-set. 12v 'digital' is used for the switch matrix, while 12v 'power' is used for infra-red opto l.e.d's (including flipper buttons) and occasionally for motors. Loss of 12v power doesn't prevent the machine booting up, but any opto switch will be 'dark', rendering it unplayable. F'r instance, with this missing on creature from black lagoon, the two ball poppers kick as the machine resets, because each seems occupied. And even after that, the flippers won't work (from the buttons, anyway)
* in current measurement, a meter has as low a resistance as possible. Connecting it to measure voltage places that v/low resistance between the measurement point and earth, rather than in series, bridging a break introduced into the circuit being measured.
