when the games loses the solenoids i'd like you to probe pins 2 & 10 on the J2 connector on the rectifier board.
multi meter set to volts DC and put the red probe to pin 2 (43VDC solenoid bus) and the black lead to pin 10 or any 'ground' on the machine.
this is pretty much the same as probing test point 5, but the meter probe terminal may cause a better connection to happen, if so determining where the fault is.
J2 plug feeds power to the cabinet, hence me asking about the coin lock out, i'm curious if only the playfield loses the 43VDC or it also drops out on the door also?
i don't suspect the rectifier board to be at fault or the fuse F4, a 5A fast blow would go open.
i'm thinking a bad connection somewhere.
if you have 43VDC at pin 2 and 10 (ground) then whilst it's still 'down' check voltage at the 1A fuse under the playfield (and/or any solenoid lug on the banded diode end) and ground.
also remove J2 from the rectifier board and look inside the plug, at pin 2 and see if it's 'okay', like not broken, and not squashed which would cause minimal pressure to the rectifier board header pin.
actually, when the game is 'down' press say any flipper button whilst lifting on the J2 plug loom (essentially pin 2 wire) and see if the flipper works?