http://www.pinwiki.com/wiki/index.php?title=EM_Repair#Gottlieb.C2.AE_Score_Motor_2

Have you seen the Pinwiki? It's a great starting point.

You will also want to check the score reset latch/trip relay. If this relay is getting stuck in the latched position, and it doesn't release right away after all the score units have returned to zero, then you'll get this problem and it will only happen at game start up.

- TimMe

Gents I have a intermittent problem on my Gottlieb Top Score,
On a game reset, the score motor seems to stop rotating just before it should resulting in the silverball not kicking out on to the shooter lane, I've looked and read, adjusted and cleaned, lubed and un-lubed, measured and checked and then the miracle happens it resets just nice.
I close up the game, put in the glass and a few games later...<sigh> no ball, I believe I need a new plan.

If you manually push the score motor another turn when this happens, does the ball kick out?

That's the exciting way to get the game to work while reaching in through the coin door lol!
Yes if the motor is rotated the sequence will complete kicking the ball out.
Lemme think (I'm not near the machine now to confirm) there are a few methods where I can manually reset the game..

A game is played and ends. Game over is lit. Ball is in outhole. No tilt or anything unusual is noticeable. There are credits showing. The game is not set for free play.
The credit button is pushed and the startup sequence begins, all scores and play surface bonus's and lights reset correctly and then the game stops without kicking out the ball. At this point I can manually do two things reaching in through the door and get a restart.

1)If I give the top disk on the motor a push the motor will take over and continue another rotation, kicks the ball out and motor stops at it's correct position. And the game will play to its logical end.

2) I manually push in the AX relay, but not hold it, the motor will run and stop, I believe a third of a rotation, then if the credit button is pushed at that point, the game will reset and complete with the ball being kicked out to the shooter lane. Play on!

With either method the next game may or may not reset properly. It can be played multiple times without incident and also can be had to be manually reset multiple times. This usually causes a bad karma and i shut it down...until the next time!

I had a similar problem on my GTB World Fair and the culprit was a maladjusted motor runout switch at score motor 1C.

thanks wayner I'll check it out, the manual has that as the 1C inside switch. Actually you know this is an adjustment I have been avoiding, messing with the score motor is one of my last resort things to do, basically I'm afraid of making them worse.
Maybe this is where I have to wade in. This machine was a major project to restore, it has had this issue all along, and I haven't touched the motor except for superficial cleaning.
Any tips on how to properly clean and adjust the score motor?

willbeEM

Unplug the machine and rotate the score motor by hand while looking down upon the switches. Does each switch open and close as the motor turns? Take your time and observe them all.

One uncommon but vexing issue can occur if your score motor is off-center. See if this is occurring while turning it and looking straight down at the cam. Any wobbly movement will cause switches to open/close to varying degrees as it turns.

I understand your reluctance to tamper with the score motor-I had a similar reluctance when I joined the hobby.
It can be cleaned & adjusted without dismantling but in my experience not very satisfactory & it misses a very important upper lubrication point which is hidden unless the cam is removed.
I think the key issue is to remove the motor board from the cab so you can get really good access to the score motor. As NicoVolta suggests concentrate very carefully on what the switches are doing & in some cases the mal adjustment will stand out very clearly-that was my experience on the 1C adj I mentioned earlier.
Perhaps not a good idea at this stage for you to dismantle the score motor until you are more comfortable to do so.

I now have a plan! I am going to follow up with your suggestions and proceed very slowly and with great caution. I've just completed shopping a Jungle Queen and moved it out my work shop last weekend so now I have the room to take out the motor board of the TS and a place to put it. And as a bonus the JQ is working 100% so I will be able to use it as a reference.
When I first got the Top Score it was a pretty beaten up game. I followed the directions of others, didn't plug it in right away and cleaned and inspected it as much as I was comfortable with, then turned it on and when nothing happened, well I had nothing to lose so I began working with all the switches, coils and steppers, slowly slowly and then one day it came alive. That was awesome! Now it's beautiful and plays great except for this reset issue. See that's the great thing about this hobby, what was bothering me before, well now I'm excited and feel confident to take the next step. I'll post updates as things progress.

thanks again
WillbeEM

Here are pictures of my Top Score motor positions with and without a proper reset

top score no ball (resized).jpg

top score ball (resized).JPG

I believe I found a problem, the 1B switch is missing a switch lifter, don't have a replacement, any way to come up with a temp fix to troubleshoot if this is the issue?

topscore missing lifter 1B stack (resized).jpg
topscore missing lifter 1B (resized).jpg
top score 1B switch sch (resized).jpg

The fix is in, at least until I find a replacement. Found a very small finishing nail that fit in the hole, cut it short, soldered it in. Found a length of hot glue, cut a piece off and pressed it onto the nail. Reassembled the switch stack and after some switch adjustment and 15 correct game resets I'm kinda pleased. Thanks for the encouragement for me to to give it a try.

Will-be-EM

top score fix (resized).jpg

Excellent work! Good job capturing how the score motor wasn't turning all the way on the non-working attempts... hopefully will be useful to others.

<sigh> it's back... its something either loose or broken that I can't find. The game resets right up to the ball eject and stops, but sometimes i can drop the game surface in place and the motor starts and the ball pops out. Sometimes at the end of a game the game over lights and then nothing....hmmm

Unfortunately that can quite often be the case. Think you have nailed it (excuse the pun) but does not solve the problem. Have you now been through all the switches on the score motor to clean & validate contact? Also analyse your score motor label inside the cab to verify the functions of all switches and try & isolate that one which controls the diagnosis. In some cases I have found visual observation of contact is not enough & use a test light.

I know your not heading down this path, but don't forget to check the ball trough switch with the playfield in place. Use alligator clips to connect to the switch, then put the field down, and check to see if the switch makes and breaks with the ball in and out. I had one that was intermittent, and it drove me crazy till I found it. I think TimMe helped me get my thinking straight on it.

LOL I've given that switch the evil eye a few times but never actually checked it with the field down. It's on the list!