One of those switches is for the coil EOS, one of those is to send a signal to the CPU to execute the code associated with that pop bumper, like giving you points, playing a sound, and making the coil fire. The one that's not registering should be the EOS switch which doesn't show up in switch test. If you try taking an alligator clip and jumper ground to the metal tab of transistor Q79, can you make the pop bumper fire? If you can, this indicates the wiring is okay and it's a problem with your driver board. If it's a driver board problem I would replace Q79 and Q78
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This is incorrect. The switch closest to the playfield right under the plastic spoon is the activation switch. It does not show up in the switch matrix. It takes ground and sends it to the special solenoid input for that pop. The special solenoid circuit has a 7402 logic chip that fires the coil through the predriver and driver transistors for as long as that path is grounded. This switch should have a capacitor and resistor on it to give a minimum pulse. The logic chip in question for this circuit is U50.

The switch that's farther away is the switch that is in the switch matrix, which tells the program to do all those other things (points/sound). Does nothing to activate the coil, or deactivate it. There is no end of stroke switch like an EM or Gottlieb system 1 pop has.

You can test if the transistors are ok by going into solenoid test and seeing if the pop fires there. If it doesn't, likely one of the transistors is bad. If it does work, test the special solenoid input connector 1J18 (pin 9 specifically) by going into a game with that connector disconnected and using a wire, ground pin #9 momentarily. This simulates what the spoon switch is doing.

The activation switch could be missing the ground from one side as well, or be out of adjustment/need cleaning. Start with the solenoid test first though. Usually special solenoids lock on on this era Williams game (system 3-11A all use this type of circuit to activate pops and slings, and sometimes other things) and blown the 7402 or the transistors, but sometimes it's something simple like the ground signal is missing due to a broken wire.

You can read up on special solenoids on pinwiki.com.

Thanks for setting me straight

Knxwledge highlighted the area of the board and the transistors you would be testing.

You can test the power to the coil by momentarily grounding with a jumper the metal tab that sticks out of Q79. Do not leave it on too long though. If the pop fires, the power path to the coil is good. If it doesn't fire, you are missing power to the coil and need to figure out why. (Broken daisy chain power wire would be the most common reason there)

If it does fire, likely Q78 and/or Q79 is bad. http://www.pinrepair.com/sys37/index2.htm#trans info on testing transistors with your meter. Testing in this way will usually tell you for sure that it's bad, but not necessarily if its good. (Transistors can test good but still not work).

If you determine one is bad go ahead and replace q78 and 79 while they are out of the board.

It is also possible that u50 is bad. http://www.pinrepair.com/begin/index.htm#howdmm in the testing logic chips section tells you how to test those quick and dirty in the machine.

The switches themselves don't really go bad, unless they're broken or pitted. You can check switches with the continuity check on your multimeter. One lead on each solder tab when the switch is closed should produce a beep. It's very likely an issue with your driver board though.

I dont think the games self test is smart enough to distinguish between a problem with the driver board and a problem with the switch. It telling you to adjust the switch might just be a catchall for any problem it sees with the pop bumper. By grounding Q79 youve determined your wiring is good. Replace the 2 transistors

It doesn't even test the driverboard. It just tests the scoring switch.

I agree that the transistors are bad. maveric18 like I said (or thought I did....) in the PM grounding the tab just tests the power path. The transistors could still be bad.

You can test the switch stack (I do not think this is your issue) by measuring the input of u50 that connects to the activation switch - it shouldn't be grounded unless you hit the pop bumper skirt.