(Topic ID: 226249)

Williams Skylab Pinball - Keeps turning cam

By hmohnjr

4 years ago

Topic Stats


Linked Games

#1 4 years ago

Hello and thank you for any help you may be able to give. I recently purchased a Skylab Pinball machine and have several questions. I have searched all of the current posts on this machine and can't find the info I need.

When I turn the machine on everything lights up and the reset cam turns to zero everything out and then stops. The flippers both work. When I push the red button on the front nothing happens. When I push the smaller white button the reset cam starts turning and won't stop. In addition, the solenoid in the coin mechanism cycles over and over and won't stop. The machine will not "pop" the ball up to the plunger no matter what I do.

1. I have a small white button on the front of my machine that I don't see in pictures of other's machines. I'm wondering if this is original or if was added by a previous owner.

2. A previous owner has removed the Lock Relay - Z-29-1250 solenoid. The two relays on the left are permanently open and the three relays on the the right are permanently closed. I did read an interaction in which this was discussed and I think this is ok.

3. When I first turned on the machine the credit count was at about 19. Every time I turned the machine off and back on and hit the front button the count dropped by 1. It is now at 13 and is no longer dropping.

4. I have checked the relays on the coin mechanism and they are all open.

Thank you for any help.


#2 4 years ago

Hi Henry, Welcome to pinside!

Quoted from hmohnjr:

3. When I first turned on the machine the credit count was at about 19. Every time I turned the machine off and back on and hit the front button the count dropped by 1. It is now at 13 and is no longer dropping.

Have you looked at the Credit Unit when this happens to see what's going on?

Also, the schematic and manual are available here, but printed copies would be better unless you have a giant computer monitor near the game

#3 4 years ago

The white button is not stock, it was probably added as a "Free Play" button and sounds like it is wired across the Dime or left coin mech switch.

Your game powers up ready to play (flippers working) probably due to the removal and defeating the LOCK relay. Normally, the game, if not already in game over, would power up in TILT and run the balls down to zero and then go to Game Over.

The red button is probably doing nothing because the game is already set up and ready to play the first ball. If the logic didn't lock the button our, it would keep removing a credit (like the white button is doing) and simply run the balls down to zero and then back up again to 3 or 5 to play.

BTW, the thing you are referring two as the "Reset Cam" is actually called a Score Motor.

The Relay on the coin door is called the lock out relay and it will be de-enrgized everywhere on the score motor cam except when it comes to rest at the Index (home) position. So, it will click on and off as long as the score motor is turning.

Are there labels on the 2 left and 3 right relays?

So, really, it sounds like the only problem you really have is why the ball will not be served to the shooter lane after it runs a reset cycle. Which may be because after it has zeroed the score reels, it should be stepping the "Balls to play unit" (stepper in back head) up to 3 or 5 balls. Check to see that this unit can be actuated by hand (Finger pushes in on solenoid plunger to either step up, or step down the ratchet). There may be 3 larger stepper units in back. One should be the Ball Unit and the other may be the 00-90 or Match unit. The match unit will have only 1 solenoid and can only step forward. And one is the credit unit with the white metal reel of numbers 1-27.

#4 4 years ago

Howard - Thank you for the feedback. I downloaded and printed the Instruction Manual, the Troubleshooting and Reference Manual, and the schematic a couple of days ago, as well as a lot of info from the forums. However, I couldn't find anything that addressed my issues. I suspect that CactusJack nailed it with the white button as part of the issue.

CactusJack - Thank you, as well. This will get me headed the right direction. Do you think it would be advantageous to replace the Lock relay solenoid? Also, there are no labels on the relays.

I am not new to electronics. But, honestly, this pinball machine is a whole different animal than what I am used to dealing with.

#5 4 years ago

No, you probably don't need to refit a coil in the lock relay. It just offers the anticheat feature of when the game us turned off in the middle of a game, it won't come back up still in game play.

I am wondering about the 5 relays you say are energized right now. That doesn't sound right to me which is why I asked about the labels.

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