I have seen one of these machine, but not for may years now...
Your pinball thinking is correct with the machine, so repairing it shouldn't be too much of a problem.
At this point I'd be checking the wiring, as you said then when you lowered the playfield down it started working - so check for shorts, wires that have had the insulation worn through, connectors, etc...
It may be the bridges and caps as you have said, but BR2 and its associated cap is more of a resetting problem than a non-working coil problem...
