Here are the 4 most likely switches to interrupt power to the playfield.

Pinball (resized).png

On some games of this era I think it's the ball trough switch between the out hole and the shooter lane that advances the ball count unit. If you start a game it should reset, but power won't be sent to the playfield until the ball rolls over the trough switch and advances the ball count unit to ball 1.

You can check the ball trough switch by removing the ball, lifting the playfield, pulling it out a bit and gently leaning it back against the head. Then start a new game. Once things have reset manually close the ball trough switch from underneath the playfield and the ball count unit should advance to ball 1. If it doesn't that could be a problem.

If the ball count unit advances but you're not getting power to the playfield until some later ball, then it may be that your ball count unit isn't properly aligned.

/Mark

Or the switches on the ball count unit itself are not correct.

Check for wear, slop, dirt and grime in the stepper parts, particularly in the arm that advances the gear from one position to the next and in the gear that drives the wiper arms. Sometimes the wear is where a small arm is riveted to a larger arm. A cleaned and adjusted stepper should snap from one set of contacts to the next when you push in the solenoid plunger and just let go.

These pictures are from an AAB, maybe they will help. They show at 5 balls to play, and at game over.

Ball Count at 5 to play (resized).JPG

Ball Count at Game Over (resized).JPG

Ball count switch at 5 to play (resized).JPG

Ball Count switch at Game Over (resized).JPG

You're welcome. Can you clarify what it's doing? It sounds like you can play a game normally but that the game won't end after draining ball 5. Is that the case? Does the stepper try to advance and fail (mechanical problem), or does it not even try to advance (electrical/control problem)?

So the game tries to advance the stepper past position 5, but the stepper mechanically doesn't reach the 6th position. That indicates that the circuitry is working and that as you suspected something is mechanically binding the stepper. Since you've taken it apart it's possible that something wasn't put back quite right. No offense, it happens a lot.

That shouldn't be hard to sort out. With the power off try to take the stepper through all of its positions just by pushing in and releasing the solenoid plungers. The reset plunger ought to return the stepper to the starting position from all of the other positions. And the advance plunger should advance it to all positions reliably.

The photos Billc479 posted above show a couple of pins mounted to the stepper gear. These pins usually open and close switches at the limits of the stepper's motion. Check that those pins only open or close switches in the first and last positions. It's possible for example that a switch stack is mounted to the wrong side of the frame, or has the wrong number of spacers or something else that changed the relative positions of the switch and pin. It's also possible that the spring around the gear has too much tension. I think they typically need 3-4 turns if everything is clean and otherwise working.

This is the beauty of EM machines. You should be able to see this problem with the power off by just manipulating and experimenting with the stepper.

Going by memory, I had the same issue with this machine. I think I ended up having to move the wafer on the shaft just a bit ( setscrews under the moving wafer) and adjusting the wafer with the screws visible on the wafer.

We're not talking much movement on the shaft. The way I looked at it, the shaft adjustment was the gross adjustment and the screws on the wafer was the fine adjustment. If you removed the wafer during cleaning, you may not have gotten the setscrews back in the same position on the shaft.

I don't know how to link a topic, but search for team one add a ball topic that I started. It shows a picture of what I found with my stepper unit. May not be applicable, but worth a look.

Can you manually activate the stepper to first reset, then step it to ball 1,2,3,4,5, 6th position?

I'm thinking if it steps through all positions manually, and making proper contact on the lugs, I would carefully inspect the switch stack making note of the 6th position switch contacts.

Also without getting too involved, inspect the switch contacts at "AX".

(Just trying to catch up here...) So the ball count unit used to have some kind of mechanical binding to prevent it from getting to the 6th position, but that has been resolved. Now it can step to all positions as it should when manually activated, but the game ends when the ball count unit reaches the 5th step.

So while the stepper may be stepping freely now, I think that at least one of its switches is wonky. On the schematic at location 11I there is a normally closed switch labeled "6th position Ball Count Unit" that connects a Red wire to a Red-Black wire. It cuts power to most of the game. In fact it cuts power to more of the game than the Tilt switch does.

That switch is likely to be opened by one of the pins sticking out of the toothed gear in the ball count unit. It sounds like that switch isn't adjusted properly and is opening on position 5 instead of position 6. With the power off, you should be able to watch those switches get opened and closed by those pins as you advance the ball count unit through its various positions.

Better yet, post a picture of the switch in position 5.

This old post might help get you on the right track:

https://pinside.com/pinball/forum/topic/fixing-the-“extra-ball-after-game-over”-in-a-gottlieb-single-player-em

I had a Centigrade 37 where the game wouldn't go into game over. The culprit was one of the short black jumper wires on the back of the ball count unit. It had detached, so the rivets for positions 3 and 5 weren't completing the circuit for the game to step up to game over.