I was playing a game on Mata Hari when the right flipper suddenly died. Moments later the left flipper would fire sporadically, and then died completely, too. I've inspected the wiring at the flipper coils. I found that the capacitor at the left flipper coil switch had broken free. I have re-soldered that, but no change in behavior. I will also note that pushing the flipper buttons repeatedly will sometimes fire the left 100 point pop bumper.

On power up, The LED for Q19 on my Alltek SDB lights and stays lit. Once I post a game, the light for Q15 lights up as well. Q19 looks like it is associated with the Flipper Enable Relay, and Q15 with the Coin Door Lockout. The two circuits also appear to be connected. Do these indicators suggest a likely cause for my flipper problem?

I'd appreciate any guidance for next steps in troubleshooting.

BTW, I’ve got ~44v DC at the flipper coils.

I just reviewed the Alltek manual. It's normal for those two LEDs to be lit on the SDB. They are both continuously on solenoids. I thought it was odd that the coin door lockout wasn't lit until after a game was started. I cut one of that coil's wires, taped it off and secured it. (It isn't needed for home use.) No change.

I agree that the pop firing is probably something else. I've had some occasional phantom scoring that I've been tracking for some time.

I did reseat the connectors at the SBD. No change. (I had rebuilt all of those connectors some years ago.)

Per Clay's guide, I clipped an alligator clip and wire to the metal side rail and touched the other end to the coil lug that corresponds with the non-banded side of the diode. Neither flipper coil fired.

No flipper movement with buttons held during startup. I won’t be able to open up the back box again to visually observe the relay until tomorrow. I might give Dave at Alltek a call on Monday. Thanks.