I've done a quick read the PINBALL Repair EM guide and will start making my way through the recommended steps there, but I wanted to log my issues and progess.

Gottlieb Super Score is my first EM. I bought it with the head removed and had it that way until yesterday when I got to spend a little time assembling it and trying to figure out how it works.

Once plugged in, the game powers on when I push the center button on the coin door.

A couple issues that I've fixed so far:
Right flippers not working - Coil lost its plunger/link down in the cabinet.
Two of the pop bumbers on the same relay were locking on. This was caused by one of the switches not opening when the pop-bumper was active. I also noticed a switch in the relay that appeared to be purposefully bent back such that it wouldn't make contact. I went ahead and gapped it properly so that it would make contact when the relay is active.

Some remaining issues:
-The 2 switches in the outlanes on the right don't seem to be registering.
-P1 10 point reel does not spin, but instead seems to get applied to P2 10 reel. I'm not up to speed on the workings of reels, but if I keep hitting a 1 point switch all the way up to 10, the 1 point reel resets to 0, but nothing happens with 10 - not even P2 10 increasing. Advancing P2 10 all the way up does nothing to P2 100. When I push the button on the center of the coin door, the game resets (I think), a ball is ejected, and P2 ends up with points in the 10 slot.
-I'm not sure about the status of the lights that I think indicate the ball in play. As it is, I don't think the game ever ends. It keeps ejecting a new ball when drained, and it always seems to be P1, though I'm not sure at the moment what indicates the active player and the ball in play.

This what I'm noticing so far. I'll document progress when I get a chance.

Other than those issues, pf lights seem to be working correctly, and I'm happy to see that the roulette wheel seems to be functioning properly, too.

I still need to clean the plugs which I gather can clear up a lot of issues, so that probably needs to be a next step.

I'm not sure yet how to ask the right kinds of questions.

Part of me wants to see if I can figure this out on my own, but I'm not very familiar with EM theory yet, so if any issues stand out to an expert as meaning I should check out something specific, I would welcome that feedback.

OK, not ignoring advice on getting schematics, but it might be a bit before I do.

There's a balls played stepper unit in the head that was misaligned such that it was making no contact in the reset position. I realigned it and the game starts in 1P mode, the lights for 2P go out, and the ball in play lamps are working correctly. Also, scoring for P1 is fixed, including all positions as well as advancement from one digit to the next.

The next issue is that the balls played unit is neither advancing nor resetting. If I manually move the plunger on the coil that advances the unit, it steps through just fine, and I can reset it by manually pushing in the reset coil's plunger, so I don't suspect a mechanical issue there. I would guess it's an issue with whatever drives these 2 coils, which I should be able to trace out.

If I put the balls played unit in something other than the reset position, and I push the button on the front of the cab, it keeps cycling through what I guess is the reset procedure for the game and isn't satisfied until I manually reset this balls played unit.

I think the balls played unit is my main focus, but I also still have 2 outlane switches on the right not working, and the switch at the end of the shooter lane that would be activated when plunging the ball isn't working.

I also notice that I get 50 points for a ball hitting the drain hole. Not sure if that is supposed to happen.

The last issue I can think to note is that upon resetting with the button in the front, I start out with 10 points.

Nice, I can see how schematics would be helpful on these!

One of the switches on the stack that senses whether or not the balls played unit is zeroed was not making good contact. That has been corrected and the unit now appears to reset as needed.

It does not appear that the unit is advancing, though. There's a relay down in the cab labeled as B - Change Players/Add Balls Played Relay. I can manually trigger this relay and the balls played unit does advance. So it seems be a matter of tracking down what drives this relay and figuring out why that isn't happening.

One thing that's not clear to me is whether or not the zero position of the balls played unit is supposed to be before P1 Ball 1 where no contact is made (how it was when I got the game) or right on it (how I adjusted it when I thought it was out of alignment).

I am enjoying this EM troubleshooting so far. It's not entirely different than solid state. It still seems to be a matter of identifying what's not working and figuring out what drives it.

It's an unfinished basement that's kept in a constant messy state from all of my projects... photos will not impress!

Do the letters in the diagram indicate the switches in the relay with that letter?

So if I'm reading it the way it looks to me, Relay B's coil is activated if a switch on Relay C is closed, and trough switch is open?

That makes more sense that it would have to be closed, since that would complete the circuit, but what's the difference between a switch that appears open in the diagram and one that is slashed through?