I recently picked up a very nice looking and restored Skylab that in general plays very well but has a few odd issues. I have never owned an EM before and have no idea where to start. Here are the odd issues:
1. On start up, when no credits are on the credit wheel, closing the coin mech switch automatically starts a game without pressing the start button. Other times, pressing the start button does nothing even when credits are on the reel but the game will only start by closing the coin switch
2. The bonus for turning off all of the S-K-Y-L-A-B switches is supposed to be 2 letter advances on the "SPACELAB", my machine currently does 2 advances 3 or 4 times consecutively like something is stuck and it wont stop after awarding the 2 letters
3.Ball count - The game is set for 3-ball game. Sometimes it lights up the 3 at game startup, other times no ball count lights are lit. It usually lets you play a normal first ball and then the 2 illuminates on the backglass. I can drain the ball over and over again and usually it takes at least 5 balls before the 2 lamp goes out and the 1 lamp illuminates.
4. Game over issues - In conjunction with the issue with the ball count, the same thing occurs on the last ball - you never really know when the game will actually end. When it does decide it wants to end, it goes into some odd loop where the TILT light illuminates and the score motor spins for about 5 seconds and then the GAME OVER light illuminates and the game is over.
I have reseated the connectors between the backbox and the base cabinet multiple times, cannot see any lose wires or bad joints, the game is in very good cosmetic condition with no evidence of burnt or charred coils, etc.

I dove into the stepper unit for the ball counter last night. I took apart all the linkages and springs and thoroughly cleaned all of the parts and put it all back together. The parts move much more freely after a good cleaning however something is still "gummed up". I took off the "spider" and the spring loaded gear would very quickly "return to home" when the cooresponding coil was manually activated for it to do so.

It appears when properly tightened, the spider is putting too much pressure on the plate with all of the contacts so it wont move smoothly or return to home when it is supposed to. I cleaned the spider and the plate and it still does it.

The only way I can get the thing to work mechanically is to not tighten down the spider in place but then the pads on the spider "fingers" do not make proper contact and the thing doesn't work.

I tried tightening the spring on the gear to give it more force to return to home but then its too tight for the "advance" coil and linkage to function properly so there is no sweet spot with that spring that will allow for proper step up and step down at the same time. Is there some method to adjust the spider to not apply so much pressure on the plate? Can I lube the plate and/or spider contacts to attempt to get smoother movement there?

This thing has gone from bad to worse. The ball count stepper is working fine now but now there are worse problems. I can't even get a game to start. The machine lights up and is just totally unresponsive. I can lift the playfield and manually energize relays to get the game to go through startup but it's completely jacked up. It won't start a game and count up to 3 balls and it won't kick a ball into the trough.

Oh and another thing now, the 10-90 score reel is stuck energized when a game is active. The coil heats up and I fear will burn up if I don't get this fixed. Through trip and error I located a switch in one of the relays under the playfield that that can be forced open to open the switch at the score reel and de-energize it's coil. My issue is I have no idea what this all means and what the problem really is or how to find the actual problem. The issue appears to be tied to the make/break circuit for switching the side of the playfield that advances the bonus at the rollovers in then in-lanes or at the top of the playfield.

And also, another random or maybe not so random issue (can you tell yet I have no clue what I'm doing on EM games?! Haha) the 6 switches (S, K, Y, L, A, B) on the sides of the playfield are not all working all of a sudden. In normal operation, after you hit one of those 6 normally closed switches, it's light goes out and a relay triggers the score real to keep track of how many of those 6 have been opened. Once you hit all 6 targets and open the switches, you are supposed to be awarded with 2 position advance on the SPACELAB bonus. Well now all of a sudden only 1 or maybe 2 of those 6 switches do anything. when you manually close the playfield switch, the light does not go out and nothing happens.

Where does one even begin to solve issues like this? Are they related? Are these all separate issues? does one need to be fixed before the other? How do I determine what is related to what on these things?

Well i have an update on my Skylab but still not out of the water...

The good news is that the game startup sequence and the ball count stepper are now finally working 100% for the first time since I've owned it.

Now the bad. The 10 point relay is still stuck on. The 10 point stepper coil is burning up (if i leave the game turned on) because its being held active by the first little relay in the lower left corner of the backbox (if you are standing behind it looking at it.) This is also holding the chime coil associated with the 10 point counter so that coil is also at risk of burning up.

What i cannot for the life of me understand is how to trace the issue backward from the 10 point relay in the backbox to whatever the heck is stuck open or closed and making this occur.

The other oddity that is still unresolved is the standup targets behind the rubber bands. out of all 6 - only the "S" and the "B" work. As in, when the switch is closed, the light goes out as it should. The K, Y, L, and A do nothing when i force them closed. As a result the bonus cannot be achieved for turning off all 6 of the "SKYLAB" lights.

I have no idea if that problem is related to the stuck 10 point relay or not. I will seriously paypal someone some money to look at the schematic for this game and try to walk me through this remotely, i am at a total loss and have had no luck finding anyone local to help me troubleshoot. Everyone around me (Charlotte, NC) only seems to work on SS games (which I do to) but this EM thing has me dumbfounded.