Here is the PROPER list of solenoid test #'s for my Bally power play:
1: Outhole Kicker
2: Knocker
3: Tophole Saucer
4: Post down
5: Chime 10
6: Chime 100
7: Chime 1000
8: Chime Extra
9: Left Thumper Bumper
10: Right Thumper Bumper
11: Bottom Thumper Bumper
12: Left Drop Target
13: Right Drop Target
14: Left Slingshot
15: Right Slingshot
16: Post up
17: Coin lockout door
18: Flipper Enable

I ran the solenoid test mode and here are the results:

1: Right Drop Target (x)
2: Right Slingshot (x)
3: Nothing happened (x)
4: Left Thumper Bumper (x)
5: Right Thumper Bumper (x)
6: Bottom Thumper Bumper (x)
7: Left Slingshot (x)
8: Left Target Reset (x)
9: Left Thumper Bumper
10: Right Thumper Bumper
11: Bottom Thumper Bumper
12: Left Drop Target
13: Right Drop Target
14: Left Slingshot
15: Right Slingshot
16: Nothing happened (x)
17: Nothing Happened (x)
18: Flipper Enable

I placed an (x) next to the solenoids that fired incorrectly. This problem used to only happen occasionally, and would suddenly dissappear and the machine would work for awhile. But eventually, the issue persisted and has not gone away, even after replacing all header pins, as well as several other components on the MPU board and solenoid board to try and fix the problem. I have already replaced and resoldered all of the header pins on both the MPU board and the Solenoid board, including both J4 connectors. I even used a multimeter to make sure solder joints stayed separated from one another. Help would be appreciated, as I am stumped at this point.