My experience with these kind of opto problems is to reseat the connectors to the small board a couple times, if that cures it, then consider removing the small board and remove the solder on the pins for the optos and the big connector, and flow on new solder.

LTG : )

Ok, I hate to resurrect an old thread, but my TBK is having same exact issue. The 3 LEDs on the Scarecrow Opto/LED board are dimly lit 100% of the time. I reconnected the LED connector a few times, but it does not solve the issue. I read somewhere that transistors could cause this problem, but after looking at the manual about 100 times, I cannot for the life of me find the right transistor(s). My only guess was Q1-7 on the CPU board, but I tested those and they all tested fine (.6 volts on the diode test).

Does anyone (especially @rockrand) had the same issue and know what the problem might be?

Still having the issue, can it be anything else besides transistors and a cold solder joints?

I just bought a HUO BDK and i have a similar problem. The 3 lights 86,87,88 are always on. Those 3 are not on the lamp matrix.
They are listed as A1 ,A2 ,and A3 .

Anybody have any advice?

Anyone ever figure this out? I have the same issue. The Harvey light stays locked on, the other two are unlit. When I go into diagnostics to test, none of them turn on. I’ve messed with the connectors on the pcb and gotten them to all turn on, but they still stay locked on and don’t receive game input. Currently, only one light is on.