Never heard of the "LED locked on blues."
BTW, there is only one LED button on BZ (Asteroids has two). It is the "start" button. Normally it:
1) blinks briefly at power on.
2) blinks when there is one or more credit.
3) stays on during game play.
4) stays on during test mode.
Due to (1), I might expect a constantly watchdog-resetting PCB to exhibit a blinking LED, but I haven't had my PCB in the cabinet in that condition to verify.
Regarding TO-220 xistors: as previously suggested, Q4 Q5 & Q6 are for coin counters, and are thus pretty inconsequential. (BTW, the coin lockout coils on BZ are not PCB-driven. They are wired to be always activated if the power supply is on.) There are three other TO-220 package devices on the PCB, but they are not transistors. They are voltage regulators VR1 VR2 & VR3 (for -15, +5 & +15V respectively). I believe these are only used for DAC and output amplification, and shouldn't prevent a PCB from "playing blind."