My Gottlieb Counterforce has been playing great, with no issues. The other day, I turn it on and notice the pop bumpers aren't working. Found both fuses were blown, so I replaced them. Now soon as you start a game, both pop bumpers lock on and stay energized. I have checked both pop bumper driver boards, and the transistors check out ok. Checked the plugs/wiring, and I do not see anything there either. The only thing I haven't checked is the diodes on the coils, which I will do. I did do all the grounding mods, just to eliminate that as an issue now, and for the future. Just find it odd that both are acting up at the same time. Is there anything else I should check?

Just about forgot to update this. Fixed the issue with the pop bumpers. Turns out there is a ground wire going back to a connector on the MPU board that was wonky. I had done all the system 80 ground mods, but didn't think about the pop bumper boards. I supposed it might be wise to run a separate ground wire to the common grounds I made doing the mods. Regardless, it is working fine now. Thanks!