I
thought I had heaps of pictures of the dis assembly of a stepper unit - but I don't have good pictures. I will document a stepper rebuild on one of the future EM Restorations. For now, I'll just describe some of the work done.
First problem with just about EVERY EM game is the "Hold" relay. Even notice the annoying "humming" sound in the background of an EM whenever you turn it on ? Sometimes is resonates and gets louder - all the more annoying. sometimes you can adjust and clean, but the coil within the "Hold" relay is always activated when power is applied to the machine. So it is almost ALWAYS worn out to a crispy brown color. Rather than muck around, I replace them. Keeps the machine quiet. Here's a picture of the old next to the new.
Stepper UnitsFor the most part, Stepper units can be left alone for years without problems, but all moving parts need maintenance at some point. During their route days, maintaining steppers was very simple. Spray them with CRC. They will keep working until the next time they need to be lubricated. That was ok THEN. But since we are hobbyists, we should take better care of these mechanisms. Typically, most EM newbs are reluctant to service a Stepper. But we all start out as "newbs" - right ! The easiest way to explain a stepper is to switch the game on and watch someone play the game. Check each stepper and note down the differences between them. Once you work out "what" they do, it makes it easier to diagnose or repair. With any machine that has been in storage for a long period, I rebuild the steppers units - All of them. The experience of rebuilding a stepper is invaluable in repairing them later on, and builds on your knowledge of EMs. Before rebuilding the steppers, have the game in working condition.
Rebuilding a Stepper UnitThis will be brief, but I will venture into more detail on the next EM restore.
1) Identify the stepper unit and its function in the game
2) Take plenty of pictures - "rest" position, all the way to it's "full" travel
3) Check the tension of any springs - count the turns on any of the shaft springs and write that down (crucial)
4) Do NOT lose the smaller springs or "mix" them up. I usually place then next to a ruler and take a picture
5) Soak the smaller parts in alcohol - This will remove the grease and grime
6) Wash the rest of the parts with a toothbrush and alcohol. I "stiffen" the toothbrush by shortening the bristles
7) Use a green scotchbrite and alcohol to wash the shaft.
8) Let everything dry
9) Drop a "drop" of machine oil in the shaft
10) Reassemble stepper unit and return it into the game
11) Check that the stepper moves freely and does what it is supposed to (See step "1")
12) Turn on the game and play test it.
Why would you playtest the game after rebuilding only one of the steppers ?
As mentioned above - you need to have the game working before rebuilding any steppers (unless you are confident the problem is within the steppers). If you have introduced a problem by rebuilding the stepper, then the problem is isolated to that stepper.
Here's some pictures of the Steppers in the Big Deal ;
Bonus Unit 
Ball count Unit
Boards and WipersThese are on the reverse side of the Stepper. They are easy to clean. Simply use a green scotchbrite soaked with alcohol, and gently scrub until the gold contacts "Shine". While the wiper contacts are out, clean the contacts as well. When it is dry, drop a "drop" of machine oil on your finger and smear it on the surface and over the contacts. Here's a dirty one ;
After spending a few hours working on the steppers, this is what you shoiuld be looking at ;
Reverse side - with a new power cord.
After rebuilding the steppers on this game, it typically fired up and worked straight away !
