I had the very same problem.

Either the transistor is shot so that it is always on - try measuring across emitter/collector with empeg off. IIRC right and center (top) leg as the board is mounted - should be high (infinite) resistance. Also do a diode check (if your meter has it) across base/emitter and base/collector. Or you do have a solder bridge from the +5V supply pad/trace to the emitter pad/trace (the one going to all LEDs and the tranny). For me the latter was the case - a really really tiny whisker of solder I didn't notice until checking very closely with a big magnifying glass...

/Michael