Trying to bring a Bally Eight Ball back to life. I cannot get the outhole solenoid to fire and return the ball to the plunger. However, I did a quick short of the solenoid to ground and the solenoid fired just fine. 43v on the yellow wire and proof of a good solenoid lead me to believe it is either the switch or the transistor. I followed the brown with yellow wire back to J1, Pin 5 on the solenoid board and did a quick resistance check on transistor Q4. It is not shorted to ground, so not blowing fuses, but maybe that circuit is my problem? Is there a way to test the transistor Q4 circuit without removing connections on the solenoid board? I hate doing that only to find out it was something else. For example, the switch for the outhole kicker is part of the switch matrix. When I close the switch, with the game on, other items on the board fire, which leads me to believe the switch is making contact fine. Before I go tearing into the transistor circuit, is there anything else I should be checking? That 43v is too high to use a logic probe on the circuit so I'm not sure how to check it.
I am having the identical problem with the side kickback solenoid. Fires fine when shorted and transistor shows resistance. Harder to diagnose this one since it does not fire all the time when the switch is closed.
I have two other solenoids not working (bottom bumper and extra chime) but I have tracked those back to transistors showing zero resistance so I know I have to replace those transistors or something in those circuits.
Would appreciate any guidance.

Wow. Three great replies. I'll address them in order.

tomdrum - I have replaced a lot of the connectors with Molex. I love them. In this case, since I can make the solenoid fire by touching the circuit on the solenoid board, I don't think there is a bad connection. There is a Molex connector on J1 but I don't know when it was replaced. Thanks for the link to the article. It is a great article.

Quench - Thanks for the charts! I thought I had about every book or article written on all this but have never seen the chart laid out the way you did. Excellent. I have run the tests before, but ran them again today to make sure nothing changed. On the solenoid test, they all fired except for the following (my explanation follows):
01 - outhole kicker - that is the problem I am trying to fix
03 - side return kicker - also a problem I am trying to fix
07 - extra chime - known problem with transistor circuit so I disconnected the solenoid
10 - bottom thumper-bumper - known problem with transistor circuit so I disconnected the solenoid
13 - coin lockout door - disconnected
14 - flipper - I didn't hold them in to test but they are working fine. I just replaced one of the solenoids on the left flipper since the primary burned out but the secondary still worked.

On the switch test, all I get is "0" showing up, which I take it to mean that they all checked as good. Right?
End result - I'm still trying to figure out why outhole kicker and side return kicker solenoids don't work.
I have been going through all of the various manuals I collected over the years and have seen some of the tests laid out for testing the transistors in the circuit. I'll try those and see if I can confirm that is the problem.

snyper2099 - Thanks. I agree. I know the exact replacement transistors (SN9302) are no longer available. I have seen several recommended replacements. Up to this point, I have been removing them from some old bally boards I have, testing them out, and then using them to replace bad ones. None of the recommended replacements have identical specs to the old SN9302 and several actually have lower amp ratings. That concerned me so I never bought them. I'm open to advice on ones you know work. I don't mess with the transistors if I can avoid it, since the boards are old and every time I desolder something, I worry that I am causing more damage than I am solving. But I know its the "name of the game" on these old machines.

Just some background on this machine. I bought it over 30 years ago. Lots of initial work to get it going. Tried the sandblasting repair for board corrosion from leaking battery and finally gave up and replaced the MPU board. Worked fine until first the bottom thumper-bumper, and then the extra chime, started blowing fuses but I disconnected those solenoid and grandkids kept playing the machine without it. It sat for 3 or 4 years without being played. I am now trying to get it back to working. New batch of grandkids want to play and I just retired a few months ago. Finally got time to mess with it. Thanks for the help.

Forgot to mention. MPU board replacement was a MUTHA board.
Quench, I did find those charts you sent. In the original Bally User manual. LOL. I spent so much time looking at all the diagnostic and repair manuals I never went back to the beginning. Thanks.

Sorry for the delay and getting back with my status. I removed Q4, Q7 and Q9 from the solenoid driver board. I then removed the same transistors from an old board I have used for parts in the past. I thought you might find this interesting. I have attached the measurements I found on the old and new (relative) transistors, after they were removed from the boards. I could make no sense of them and just threw them all away and ordered new TIP102 transistors and have now soldered the new ones onto the board. What a pain. I hate soldering on those old boards. Traces lift off and pins are so close together it is difficult to keep solder from shorting to another pin.
I reinstalled the board this afternoon. Yay. All my fixes worked. I am still not getting solenoids firing for the chime 100 and the extra chime. I have noticed that the white/green wire for the extra chime is disconnected. Done before I got the machine and probably a bad solenoid. I tested the transistors for both of those and they appeared to be ok, so I'll make sure I have 43 volts running to the solenoids (should be ok since chime 10 and chime 1000 work) and then check resistance and test fire the solenoids themselves.
Slowly but surely getting there.
Thanks for the help. I may come back to Ya'll after the chimes are fixed. I have a couple of bad digits on two of the displays. Never worked on those and understand they are high voltage. I am hoping they can be cleaned up and are just bad connections, but I know that is probably not the case.

Transistor resistance measurements (resized).png

No, the displays don't look like bad glass. A couple just have one digit that is blacked out. I'll do the procedures you outlined.

I started working on the chimes. The extra chime wire going to the transistor was disconnected. Before reconnecting it, since the transistor checked good when I had the board off, I just touched that solenoid wire to ground. The solenoid did not fire. However, when I did the ground touch, it blew something on the machine. I thought it was the playfield fuse, or maybe F4, but both of those check good. I get the 49 volts AC at F4. However, I get no DC voltage at TP5 on the rectifier board. It looks like I may have fried the rectifier. Hard to believe it destroyed the rectifier without first blowing the fuse.

I notice there is a 600 ohm, 10 watt resistor in the circuit. R1 on the schematic. There is also 100K ohm, 1/4 watt resistor on the VAC side of the circuit but on the rectifier side of the F4 fuse (R3). Any chance either of these could cause the problem? I can get the rectifier and 1/4 watt resistor overnight, but it will take days and a lot of shipping charges to get the 10 watt resistor. Since it is wired into the middle of the rectifier, I don't see a way to test it without pulling out the rectifier or disconnecting one leg of the resistor from the board. I guess I'll start on that, unless there is something else that could have caused this or anyone has better suggestions.

Dang. Game was working great. Chimes were no big deal. Can't believe I caused all these problems trying to fix the chimes.

Thanks! Like the old aftershave commercials, "I needed that!"
Figured out why the chime shorted out. Someone put in the solenoid the wrong way. When they replaced it, the Hot wire was not to the banded sided of the diode. Solenoid is fine.
I started to unsolder the rectifier but paused and figured out I would check it one more time. Check it twice and solder it once. I had tested for 49VAC and got it on both sides of the fuse, and the fuse looked good, so I thought F4 was OK. Pulled the fuse and tested it with a voltmeter and it showed it was blown. Wow. Saved me a ton of work. Replaced the fuse, rewired the chime solenoid, cleaned the connectors to the other chimes (they were already molex), and game is working again. Still not sure how I got 49 VAC on both sides of a blown fuse.
Next will be to work on the displays as outlined in this thread. It is actually working OK now, and playable, and I feel comfortable in putting bottom glass back on, so I feel like I made real progress. Weird. I have handled major deals in the past while working, and have never felt as satisfied as getting this machine to actually light up and play. I think I earned a beer!

I have another problem. This one is out of the ordinary.
As noted earlier, I made all the necessary changes (replaced transistors and solenoids) and got everything on the game working except for a couple of black digits on the displays. So I closed up the playfield, replaced the glass, and was enjoying playing the game. It worked perfect, except for the displays.
Came back the next day and turned it on. Game went through the startup process and everything appeared to be fine. I pushed the button to play a game, and it all started up except the outhole kicker did not return the ball to the shooting lane. I opened the door and pressed the test button, and all of the solenoids fired, including the outhole kicker. This put the ball into the shooting lane. I turned the machine off and back on and played a game. Worked fine. At the end of each turn, the outhole kicker returned the ball to the shooting lane until the game was over.
Then I tried to play another game. Same thing happened. Game started, but the outhole kicker did not return the ball to the shooting lane.
I know the solenoid is good, and the transistor circuit is good (new transistor) and it works on the test sequence, and it works during game play, so I cannot figure out what is different about firing that solenoid when a game is started. What am I missing?