Check power supplies in the backbox first:
For solenoid power to coils check PS 3J3 pins 6,7,8 for +32 to +35 VDC. You can grab ground at the board mounting screw conductive pads.
For flipper power check 15J3 (flipper power supply board) pins 1,2,5,6 for +65 to +75 VDC nominal. Flipper ground is 15J2 pins 7,8,9