This is my first machine and first repair so please be patient as I'm still learning the inner workings of my machine.
Upon booting up my machine the other week, both diverters would not fire. As a result my F14 is unplayable until I can fix the issue.
I went through the in machine diagnosis process. All solenoids were firing properly except for the upper and lower diverters. I checked out the coils and solenoids for the two diverters under the playfield. Solenoids moved when I manually pushed them (not stuck) and the coils appear fine. I also used a DMM to test the diode for each coil and no issue.
I followed the blue/black and blue/green wiring from the two coils to the backbox where I saw they hooked to 1J19. I followed the circuit board from 1J19 and saw one diverter connection went to a 2N441 at Q78 and then a TP122 at Q79. The other went to a 2N441 at Q76 and then a TP122 at Q77. I tested all 4 with my DMM in circuit. Q79 and Q77 were good for sure. Q78 and Q76 inconclusive as I got same resistance when switching between positive and negative DMM probes. My research says that is not uncommon when testing in circuit.
A violet/yellow wire daisy chains from one of the diverter coils to the other diverter coil that is not functioning. I followed this wire to the backbox and connected to another board which I am not positive what it does. I have included a picture of this board in this post. This board had a single fuse on it. I checked the fuse and all seemed good.
I am not certain where to look next to troubleshoot this issue. Any assistance to this newbie would be greatly appreciated. Thanks