My Williams spacelab has started acting up and I can't seem to find the problem.

A little history on this first (sorry if this gets long winded).

Spacelab is the add-a-ball version of skylab. According to the pinball database there were only 30 made. I don't know if they just pulled a skylab off the line and converted it when an order came in, but there seem to be some differences amoung various spacelabs. The database shows a credit wheel in the backbox, but mine does not have one. Mine also doesn't have a 10 cent or 25 cent relay - instead there is a credit relay, which doesn't show up in the schematic.

When I first turn the game on it will go through a reset sequence. If I turn the game off and then back on while it is reset, I can then do the standard Williams trick of pressing the left flipper button to turn on the lights, but this ONLY works if the game is already reset.

I have the game set for 2 plays for a quarter. When the quarter is inserted the first game starts - no need to press the start button. The credit light on the apron is lit showing the second game available.

This is how it's always worked since I purchased it, but I don't know if this is really correct.

Now on to the problem:

About a week ago I noticed while playing that when the ball was kicked out from the outhole to the shooter lane, sometimes the coil seemed weak and the ball would not reach the shooter lane but fall back into the outhole. The game would then think I drained another ball and decrement the ball count and kick it out again. This made for some very fast and very low scoring games.

I lifted the playfield and cleaned what I thought were the appropriate switch contacts. This is when the real problem started. The game will no longer reset properly. When I power up all the score reels go to zero but the ball count unit is not firing, so the score moter keeps running, trying to get the balls to zero. I do see the outhole relay tripping every revolution of the score motor.

If I manually reset the ball count unit the score motor stops and everything seems normal. If I then drop in a quarter the game trys to start - the ball count pulses up to three, but the ball release coil never fires and the score motor keeps running - again pulsing the outhole relay. Even if I manually flip the ball into the shooting lane thereby opening the outhole switch it still keeps running. If I then decrement the ball count unit to zero everything stops.

Looking at the schematic it looks like the only thing in common with the ball count reset and the ball release relay is the outhole relay. I've metered the contacts and they check out OK.

I'm at a loss on what to look fore next. Any help is appreciated.

I will try to upload the portion of the schematic with the coils and switch in question.

spacelab5.jpg

Looking at the Williams start-up sequence write up there are a couple of other things I need to check.

As I mentioned above, when trying to start a game, even if I manually push the ball into the shooting lane the score motor still runs - so I am not sure what the machine is 'looking' for.

When I start the game the scores all go to zero and the ball count steps up to three.

A-ha. That's where the problem is - the ball count doesn't step down, either during reset or start-up. I thought the only switch on it was the zero position switch, but I will take another look.

Rolf,

Normally when the machine is turned on it goes through a reset. Since the problem started, while resetting, the ball count unit does not decriment. The score motor runs continuously and the outhole relay pulls / lets go / pulls / lets go. If I manually decriment the ball count to zero the reset sequence completes and the machine sits idle.

If I now credit the maching the game starts. The ball count goes to three (game is set to 3 balls per game) and then the score motor turns endlessly with the outhole relay pulls / lets go, etc but the ball release coil does not fire.

Dr_of_Style - there is no switch on the reset portion of the ball count unit. The only switches on it are activated by the cam when the unit reaches zero.

One other thing I've noticed in the back box - the 100,000 stepper seems to go past the zero count. What I mean is that it gets to zero and then pulses again, Since it can't do a complete step below zero the solenoid stays in even if power is removed. I'm not sure if I'm explaining that clearly. I'll see if I can post a picture.Not sure if there is a zero switch on that, but maybe that is not registering and that's why the score motor keeps going.

Never mind - just checked it and found that it resets all at once, not in steps.

Got a little sidetracked tonight. I was trying to figure out why the ball count steps up but does not step down. I measured the continuity between the make/break of the game relay contacts to the coils on the ball count unit. I was having trouble getting a good reading, so I spent the night burnishing all of the relay contacts. Connected the playfield back up and no change.

Going to call it a night.

Didn't get a chance to do too much with this today.

One thing I noticed, and I'm not sure if this is a cause or a symptom, is when the machine goes through the start game sequence, the advance unit resets like it should but then I think it's supposed to step up one position, but it doesn't. Could this affect the rest of the start sequence?

Rolf,

I connected one lead of the meter to the low side of the advance unit relay step-up coil and the other side to the yellow connection on the outhole relay. I made sure 3-A on the score motor was closed and when I manually pushed the outhole contacts the meter read 0 ohms, so I assume the connection is good.

The ball-index relay stays inactive through the start-up cycle.

I really don't see why the advance relay is not stepping up to 1.

Thanks
Don

Gotta work today so I'll have to wait until tonight to check this.

I'm going to see if I can find an analog meter somewhere so I can look at these connections while it's running. I think a digital meter reacts too slow to detect switch pulses.

Ok, got a chance to work on this today and made some interesting observations.

1. While the machine is off if I manually set the ball count unit to zero then power up the machine, it resets the way it always did.

2. If I then coin up the game it goes through the start sequence but doesn't increment the advance unit and the score motor keeps turning. If I manually step up the advance unit the score motor stops, but the ball release solenoid never fires.

3. In this position the game is live - meaning the flippers are active and I can manually close rollover switches and have the machine score. If I hit the individual 'skylab' letters on the sides of the playfield the advance unit STEPS UP TWO POSITIONS like it should.

The ONLY thing in common with the ball release not firing or the advance unit not incrementing on startup is the outhole relay.

I've noticed when the score motor keeps running, the outhole relay pulses on each time the index switch closes (switch drops into the notch.

My question on this is once the outhole relay is energized, shouldn't the relay stay latched on as long as switch 5E on the score motor is on (riding the high part of the wheel?

WOO HOO IT WORKS!!!

Checked the contacts on '5E' of the score motor and sure enough the connection was bad. Burnished the contacts and hit them with a little de-oxit and the machine fired right up.

A few notes on this - since this is a spacelab rather than a skylab there are changes that are not reflected in the schematic/manual. For example, the schematic shows the outhole relay as having 5 sets of contacts where this game only has 3. Also the actual switch 5 on the score motor only has four positions - a through d, with the contacts for the outhole relay hold is actually position c. I guess they removed anything that would usually control the credit unit or the knocker (this game doesn't have either). Also there is a credit relay in the game not mentioned in the schematic and there are no 10 and 25 cent relays. This makes troubleshooting especially difficult.

Big thanks to Rolf for all of his help and troubleshooting suggestions. I now know a lot more about how the game should work and the sequence of the game start.

Also thanks to Dr_of_Style for his helpful suggestions.