Nice to see you with a bingo. Mystic Gate is an interesting game.

The answers you seek are here: http://bingo.cdyn.com/machines/bally/mystic_gate/

Looking at the schematic, there's only a single switch that would pulse or lock that coin counter unit step up - Control Unit cam 5B. (schematic shows cam 5, but the manual gives a per-switch breakdown on page 15). Cam 5 should have detents that cause 5B to open when the roller settles (and the timer cams stop rotating).

Sometimes it's easier to remove the backglass and fold down the lamp board onto the siderails to inspect those switches, but with a little creative wiggling, you can also adjust from behind the game. A flashlight to shine through the switches helps.

The control unit is a clutched affair. The entire thing is driven by a motor, but there are separate sections. Review the manual page I pointed out.

Credits vs payouts... there is not such a thing as a payout in a bingo. It's all credits. The deal is that there's a knock off circuit. Other games (older) had a separate button to knock credits off. In a bingo, when powered off and back on, the replay register zeroes. If the game was modified aftermarket to pay out replays directly, that was wired based on how the operator chose to do so. Some did it on accumulation, some did it on reset.

This happens through the switches on the anti-cheat relay, the replay reset relay, and the replay register. You may think the replay register switches are good, but they are a little finicky. A bingo is a mixture of different styles of switches - certain aspects require more precision than others. The replay register SPDT switch is one such.

If it is fine, then there's an issue getting the control unit to shut off, or for certain sets of cams to stop rotating. Gummy clutches will do that to you.

To fix, the control unit must be disassembled and the clutches cleaned and re-oiled or replaced with fresh clutches newly oiled. The oil is neatsfoot compound (NOT oil). This is specified on the schematic. When I clean them, I quickly douse in 91% isopropyl, then scrub clean with qtips/a paper towel, then quickly submerge in a neatsfoot compound bath. The clutch stays in there for about 5 minutes, then take out, pat dry, then reassemble. Each clutched section comes off in one piece after unbolting from the next in the sequence, if you go that route (sounds like you'll need to).

While it's apart, ensure the shaft is clean and deburred. The switches on top of the control unit will all come off in one piece. There's a screw under HIGH tension on the edge of the unit (called the search disc wipers). Be careful when loosening this screw as it will rocket off if you're not paying attention. Otherwise it's pretty straightforward, but a more advanced EM repair technique compared to just adjusting some switches.

Regarding the coin unit - Mystic gate is one of a handful of 40 coin max games. So the maximum amount of replays or coins played per game is 40. My guess is that the control unit cams are not in the correct spots. There are two coils mounted underneath the control unit on the left and middle - these gate various sections. One armature is probably not in the detent correctly? Total guess.

Have you verified/cleaned the coin unit? You mentioned that all the steppers are stepping and resetting correctly. When the game is turned on, it will try to zero credits. Once it verifies that the register is empty, the replay reset relay will let go, then enable coin entry. Putting in a coin will reset all steppers and pulse the coin unit (up to five times) based on if configured for multi-play or single play. Multi-play in this instance is a way to give multiple credits for one coin. For example, a quarter is 5x a nickel, so if configured for a quarter per play, players used to paying a nickel per game would feel better about the change in coinage. You've already tried unplugging the coin door. Is it still unplugged? That would rule out weird issues with the coin switch when tied to the multi-play relay, but I'm guessing that's not the issue.

The manual and schematic are quite detailed - be sure to investigate the areas I mention. All switch positions and their uses are documented.

You can observe the control unit spin with the game off by rotating the fan blades. It should be spinning the first couple of cams and rotating through the screw at the end, but nothing in the middle should be moving. If it does, then there's your problem. If it doesn't ensure that the middle cams are held in place with the actuator arm from the coils underneath the control unit for the first two on the left. The third is for -finding- winners, and should not be held at all times.

If it doesn't let me know and I'll give you something else to look for. Are the jones plugs clean and tight & assembled correctly?

My first bingo was the same way. Patience and persistence pay off.

Before you do that, you mentioned the control unit is moving again, but did you verify that one particular switch was behaving properly? I may have jumped a series of hurdles in logic there.

Yes, this is a big learning curve as there are just so many units and features in the game! But it all boils down to simple sequences and a common set of tasks. Power on, credits zero. Coin inserts, game resets, then certain units step up once. Coin unit, odds units, etc. Trip bank resets. As features are awarded with additional coins, relays in the trip bank will trip or units will step (particularly the coin unit). Timer unit steps when the first ball is lifted to the playfield.

As balls are shot, additional relays will trip. Timer unit will continue stepping when additional balls are lifted (until ball 5). Then the game goes into an automatic timeout mode and will step the additional steps on a pseudo-random timed basis.

Pressing the R button resets the timer and starts a search. When a winner is found, the search index coil will pull, stopping the search disc wipers. The various color replay units will then start stepping to ensure that you don't get more credits than you've earned. As it finishes counting each winner, it will continue the search. The game will not accept coins or restart until the search is complete. Testing for functionality requires ensuring that the game awards credits for each winning combination with the mystic lines units in each of the three positions. That unit is massive and has a lot of parts, but it really boils down to three positions for each set of A-B-C. The wipers need to be clean and aligned properly or you'll never get proper award.

There are lots of options and things to check from a player's perspective, but those are the basics of any Mystic Lines game.

That's normal. Once the game finishes resetting replays, the anti-cheat will be off. It will show 'tilt' in the backglass (but the tilt trip relay is not tripped). I call this 'false tilt' and it confuses a lot of new folks. Inserting the first coin will power the anti-cheat and it remains powered -unless- there's something wrong with the 50V line. Then it becomes the canary in the coal mine. If it lets go without tripping the power, something is broken in the 50V line.

Almost everything in the game is run off of 50V, which makes it pretty easy to work on.

Yeah, that'll create some funnnnnnky issues.

That's the correct coil. I don't have a spare control unit and those parts are unique to the unit... IIRC. You aren't able to remove the timer cams (be careful to note exactly where it was pulled from!) index assembly, then hammer or heat gun at it until you can pry it loose? I'm guessing that the stop and plunger are salvagable... if you can get the coil off. Could also try cutting the coil off.

Regardless, once you do that, you're probably going to need to sand/polish the plunger. I wouldn't be ultra concerned if there were a few marks made on the plunger in the process.

If not, you'll need parts from another bingo person on the forums. See what you can do about separating first though.

Yes, they do, but putting it back in the wrong spot (I believe the base is slotted to allow some adjustment?) Will cause some different problems.

The parts are unique to the control unit, not the game. Parts from most other bingos will work, so you've got about 30 years worth of games. (I think).

Bingo.cdyn.com has a listing of some folks selling parts. Just be sure to specify the part(s) are needed from the timer cam index assembly.