ok, it sounds like your problem is the coin unit step-up relay is not staying powered when it should.
the first coin deposited trips the coin relay and handle release relay.
the second coin two things happen:
1] when the coin switch goes down, the coin unit step up relay (CUSUR) powers.
2] when the coin switch goes up, the 74-1 connects to 30 and IF the CUSUR is still powered, the coin unit step-up solenoid powers and releases the CUSUR. The plunger moving back out of the solenoid moves the unit wipers.
you have a couple testing options:
1] just examine stuff:
the coin unit step-up arm switch and make sure it's closed when the unit is at rest. If you manually pull in the step-up plunger, the switch should open. If you aren't sure what the step-up arm switch is, it's a vertical switch near the coin unit step-up plunger with yellow 30 and orange/white 75-7 wires on it.
if [1] looks ok, check a switch on the CUSUR with orange/white 75-7 and brown/red 61-1 wires. It needs to close when the CUSUR is powered.
2] if you can reach the CUSUR, when the game is sitting after a spin, hold down the coin switch and push down the armature plate onto the coil top. It should stay down by itself.
if you can't reach the relay armature:
- attach a jumper wire to the brown/red wire on the CUSUR relay coil and put the reels back in the game.
- hold down the coin switch
- touch the other end of the jumper to the yellow wire on the coin switch. The CUSUR should power and stay powered. If it unpowers when you untouch the jumper from the coin switch, then one of the two switches in [1] is not working or you have a plug connection issue on wire 75-7 ... or somehow wire 30 on the step-up arm switch has a problem.
to clarify (not likely) some of the above, below are a couple pictures from david walz labeling some of the parts.
if you aren't familiar with stepper units like the coin unit and how the wipers move, see a bad video here:
https://bingo.cdyn.com/video/stepper_units.m4v the video is a older/simpler unit without step-up arm switches, but the coil unit works the same way.
note if you are comparing the second picture below to the 1114 schematic, the wiring of the top switch on the coin unit reset relay does not match as the picture has yellow wire 30 attached instead of an orange/green 74-4 wire. See the 1114-2 schematic for the wiring. It's functionally the same, but the 1114-2 circuit is simpler and eliminates a possible race condition when incrementing the "total in" meter.