I've tossed dozens of these boards, they provide decent lighting, but Chris is correct, they suck up power like there's no tomorrow! Trying to lower the lighting with resistors is a poor way to do this, LED's will give you better lighting and reduce the power consumption 90-95%! Did I mention they're flicker-free and have intensity adjustment to tune to the exact light level you desire? They also include DCS signal protection so they won't affect the MTH track signal.
