For my machine I wasn't happy with how dark the game was. Also with "Blackout" mode active, the playfield GI dimming was barely noticable.
To remedy both of these in one hit, I crafted 3 "Street Lamps" that bolt to the tops of posts/plastics, as well as fitting a Green light (obvious EXIT colour) pointing up the Blackout ramp. With a simple (transistor free) circuit, the "street lamps" are lit at all times the game is turned on (while the green light stays off), until the "Blackout X2" flasher is flashing. Any time the Blackout flasher runs, the sensing relay (Low power SMD) is activated intermittently by the flasher power. This relay switches the second relay using an external power source, which is delayed from turning on/off for about 1-2 seconds by a capacitor in paralel with its coil (to smooth the flasher ripple). The second relay can then use its NC/NO switch outputs to turn on the street lamps or the green light, at opposite times. There is a switching delay of just over 1 second.
*It's been a while since I played around with this, can't exactly remember the circuit I settled on, but I can record it and post for anyone interested. I set up the game on hire last week at private residence, so can not access details right away.
The effect becomes three added spotlights that add alot of brightness to the playfield in regular play, and when Blackout is started they go Out, and the green Blackout ramp lighting is lit. I'm very happy with it, and others comment on how the effect is so much more dramatic than they remembered. Win Win.
Only other point to note is that Chromed low carbon steel balls (ninja etc.) should never be put into a game with magnets. If new balls are needed use Carbon Steel Precision Balls with Mirror Finish, to save yourself problems. Chrome plated balls will magnetize quite readily, and start sticking to metal things, and each other.
I digress ...
Awesome game, much loved by pinheads in these parts!