So, to help with reading the schematic: there will be a switch that gets grounded when the solenoid should pull in. This line goes to the input of a NOR gate. The other input to the NOR gate is a blanking signal that disables all the special solenoid drivers until the system is ready... prevents spurious firing during power-up. When both inputs to the NOR gate are low, the output goes HIGH, turning on the pre driver transistor (2n4401) which drives the TIP122 darlington transitor to turn on, effectively providing a path to ground for the special solenoid. The other side of the solenoid is connected to the power source for the solenoid, and is usually daisy chained to multiple solenoids.

To test the circuit, you can "touch" ground the switch input and the solenoid should pull in. A logic probe is not that useful of a tool for this kind of circuit testing. Just using a voltmeter and understanding how the circuit works will allow you to find issues. To check the wiring from the output of TIP122, touch grounding that should fire the solenoid. If you ground the switch input, and do not get a solenoid pull in, then the problem is in the path... NOR gate IC, 2n4401, or TIP122... with the likelihood of failure being in reverse order.

Hope that helps.

Mac

Page 2 of the manual says the left kicker is special solenoid #1.

This should fire in coil test.

It should be 1J18 pin 5.

Special Solenoid 3 Trigger.

No Q-74 and Q-75

5 volt test point is by U-22 and the ground test point is by the battery pack.

This is an error in the manual and not the only one. Q-79 is for SS6 Top flashers.
You are going to need to troubleshoot U-45 which is a 7402 NOR chip. Do some reading on this chip, so you understand how it works and how the pins are labeled and when you get your logic probe I can walk you thru testing it.

forget the switch inputs for now. start at the coil and work backwards. I am assuming the driving transistors are Q70/Q71.

0) Game on, put DMM on either lug of coil. should show 35 volts DC.
1) Ground the non-banded coil lug with a jumper wire. coil should fire.
2) ground the transistor lug for this coil (q71) at the cpu board. coil should fire.

if steps 0 to 2 don't give results, you probably have a power issue.

Turn game off...
3) remove connect J19 from the CPU board and using DMM set to diode function (and game off), test the Q71 transistor. black DMM lead on the metal transistor tab. Both outside legs should show .4 to .6. If not, transistor probably bad, replace with a new TIP102. After done testing, replace connector J19.

If still not working....

4) Now turn game on and put the game into coil test, and select this coil. (use the middle diag switch to "stop" the test from moving. this will continually fire that coil, over and over.)

5) use the logic probe. Assuming the coil transistor is Q71, put the logic probe on u45 pin 5. It should "beep" about every second, as the PIA tries to fire the coil. That is, it should be HIGH and momentarily go LOW as the diagnostics pulse the special solenoid in question. If you have nothing here, the PIA chip is probably the issue.

6) if you have a signal at u45 pn 5, look at u45 pin 6. this is the blanking. this should be LOW all the time. Note when the game boots and is not in play or in test, blanking will be HIGH. When a game is started (or diagnostics are started), blanking goes LOW. Pobably not an issue, but worth mentioning. if blanking is high or missing, none of the other coils will fire, so it's probably not the issue (unless there's a broken trace.)

7) What the 7402 chips is doing is looking for two LOW inputs (the blanking, which is always low, and the PIA signal, which is high but goes low for just a moment as the desired coil is pulsed). Now go to the output pin u45 pin 4. the coil test is still running, and this pin should bounce HIGH every second or so (as the diagnostics pulse the coil in question). What is happening is the blanking (pin6) and the input (pin5) both need to be LOW for the output (pin4) to trigger HIGH. if you have no signal on u45 pin 4, the problem is the u45 chip. replace it (and use a socket).

At this point, you can follow the signal to Q70 if you want, and to Q71. But frankly unless the board is damaged (broken trace), the issue is probably Q71 (tip122 but replace with tip102). While you're at it replace q70 too (2n4401). Note the test in step3 is not definitive. Even though the transistor tested as "good" in step3, doesn't mean it is necessarily good. (Opposed to it testing bad, where it means that transistor is definitely bad.)

with this done, the coil should fire in coil test. If the coil fires in test, but not in the game, we can test the switch inputs. But 98% of the time, the switch input is not the problem.

Clay corrected his post to align with the logic below. Thanks Clay for the nice write up.

On a NOR gate, both inputs must be LOW to get the output to go HIGH. The Blanking line would then need to be LOW. If the Blanking signal is HIGH at pin 6, the output pin 4 will always be LOW and not "bounce".

NOR (resized).JPG

Pin 1 (in blue)

U45.jpg

I'm afraid it doesn't exist. This is a piece of an unfinished sys11 layout that I started in 2016. Probably need another year to finish.
This morning I colored this particular area and added some info in U45 to make it more clear.

I have updated my post above with some corrections/additional ideas.

Based on Clays correction, I removed the original quote with the error in it in my post above. Thanks Clay.

Sorry it took me a few edits to get everything perfectly correct in my original post. Was trying to do this from memory, and that didn't work so well! had to take apart a high speed to test everything and make notes, so i could update the post for accuracy. I believe it's all correct now.

It's been a year but I want to call out what an excellent post this is. Thanks Sheprd

Glad to help!

Mac