Most guys disable the 'anti-cheat relay'........ by unsoldering the hot coil lead, and wedging the latching arm ON.
I also undo the tilt bob mechanism so the Bingo does tilt....... but that's me!
The shutter mechanism is a Big 'PITA'...... I have intermittent problems all the time.
I would close the shutter by hand, and see if you can play a full game. The switch setting on the shutter cams are
always a problem to set correctly.
*** This is how the shutter should close. Your Timer unit may not be stepping Up. See diagram below.

ScreenHunter_10 Jan. 10 17.10 (resized).jpg

***** I also undo the tilt bob mechanism so the Bingo does tilt....... but that's me! *********
Should say : " so the Bingo doesn't tilt "
I don't want to ruin a big game by Tiliting my own Bingo........ LoL.

Timer Unit stepper.....
1. I would verify this unit is working correctly. Clean it and verify it steps-up and resets by hand.
2. Verify it is being energized during game play.
3. Ball Lift cam switch 2a ( E7) energizes Timer unit coil ( A8).

30V at anti-cheat is incorrect. That is tied to EB trip relay #1 and CU cam 5 switch C (third from the bottom).
******************************************************************************************
Yes..... you should be reading close to 50VAC. across that coil.
I'm sure your 50VAC output from the transformer is ok, you can check it at the transformer.
@ see link below for measuring points...... I have a reading of 52VAC with an input voltage of 123VAC.
As stated above..... you may have a voltage drop at the E.B. trip relay#1 . It is a S.P.D.T. switch(L2) they can be
trouble. You may have a POOR connection there causing a voltage drop; that contact should be closed when
the relay is not energized.
Also check that the switch contact at Cu cam 5 is clean and making good contact.
*** I forgot to add...... verify that 10amp fuse is 100% good, and the fuse holder has a tight fit. a partially blown
fuse and a loose fuse holder will drive you batty.
https://bingo.cdyn.com/techno/readschem/schemblock.html