Welcome to Pinside, and congrats on getting a Sky Line, that is a great game!

At the start of a new game, the ball gate is supposed to stay energized until you score some points, so for the moment I would not worry about that.

The score motor running sounds like you are not coming out of reset. The most common reason this happens is because the game is waiting for all of the score units to return to zero. Since you have two score units that are not working, you should check to see if this is your problem. On the control bank (the long row of relays mounted on the bottom board) look for a relay marked RESET COMPLETED or something like that. If this relay has not tripped even though all the score units are back at zero, try tripping it by hand to see if that makes the game come out of reset. If so, then the circuit that is supposed to detect that all score units are back at zero (which would trip the RESET COMPLETED relay) is not working right.

Do you have a schematic for your game? If not, you really should get one. The Pinball Resource sells them.

- TimMe

It's difficult to check switches in-circuit on an EM using a meter. You will often get a reading showing a closed switch even when the contacts are open. This is due to a combination of factors, including the low resistance of the transformer secondary, the low resistance of the coils being controlled by the switch, and the possibility of a parallel switch on the same circuit (located somewhere else in the game) that happens to be closed.

If you are going to check switches for continuity with a meter, you will need to unhook one side of the switch and test it out-of-circuit. However, it isn't that useful to check a switch for OPEN with a meter. If you can see daylight between the switch contacts, and the backing blade isn't crossing the switch gap and shorting the blades, and the solder lugs for the switch blades aren't mashed over and touching each other, then the switch is open. In other words, when you can see that there is no contact between the switch blades, you have confirmed that the switch is open.

Similarly, if the switch points are clean and making good solid contact, then 999 times in 1000 the switch is closed. So again, using a meter is not particularly useful, even when you want to confirm that a switch is CLOSED. It's almost always faster and more practical to just close the switch under test with a jumper wire and see how the circuit reacts.

- TimMe

Each score unit is driven by a point relay - N, M, and L are the three relays for the 1, 10, and 100 point score units respectively. Each score unit has an EOS (end-of-stroke) switch built into it that is used in combination with its point relay to ensure reliable scoring.

When a score switch closes on the playfield, the relevant point relay is energized, which locks itself on electrically via its own lockin switch. A different switch on the point relay energizes the solenoid of the score unit. When the score unit mechanism has indexed far enough to advance the reel, its EOS switch opens and that cuts the power to the lockin circuit of the point relay.

Since you have two score units without solenoids, for those two score units the point relays are going to lock on forever because the EOS switches on the score units are never going to open. For the score unit that is working, you'll need to check the lockin circuit for that point relay to see why the opening of the EOS switch on the related score unit isn't shutting off the relay.

- TimMe

You cleaned all the contacts on the score units, right? It's possible the EOS switches were not making good contact before, so the lockin circuits for the point relays were always open. Once you cleaned the EOS switches, the lockin circuits started working, and the point relays started locking up.

- TimMe

Excellent progress! You need to put 5 balls into this game to get 5-ball play.

The red special indicator above the flippers lights when you knock out all of the numbers from 1 to 12. Once you get all 12 numbers, the special stays lit for the remainder of the game. The red special just an indicator light to let you know you've completed the number sequence.

When the red special lights, there should also be one of the numbers from 1 to 12 that lights up again. The lit number is what should score a replay. As you make points on the playfield, the lit number is supposed to change. Whichever number is lit at any given time while the red special is lit is the one that is supposed to score a replay. This feature is called a "traveling special."

- TimMe

There is no connection between the number of credits and the number of balls per game. They are two different things entirely. The number of credits is determined by the replay stepper unit in the head.

Here is why you need to put five balls in the game. When the game starts, the ball gate opens and all five balls roll down past the gate into a holding area in the lower section of the ball trough. You feed each of these five balls to the shooter lane using the push-up knob. The ball gate will close when you score some points on the first ball, but since all five balls are sitting in the holding area beyond the gate, you will be able to play them all.

When the first ball drains it is stopped by the (now closed) ball gate. As you play the remaining balls they stack up behind the first ball in the upper section of the ball trough, where the switches are. The four trough switches are there to actuate the game-over relay and the match feature. The first two switches are there for when you are running the game as a 3-ball game (in which case you would only put 3 balls in the game). The second two switches are there for when you are running the game as a 5-ball game.

The reason there are two switches for the game-over circuit is because each ball that drains rolls over every switch in the trough before it gets stopped by the closed ball gate. If there was only one game-over switch, say, for the 5th ball, it would be closed when the first ball drained. So two switches are needed. They are wired in series, which means there must be a 4th ball AND a 5th ball present in the trough to close both switches at the same time, which then actuates the game over circuit.

- TimMe