Thanks, but I kind of figured that out later... Duh. Apparently the LED is on a fader circuit, and as it dims it projects less light into the blade giving the impression of the power up/power down of the conventional FX sabers. Too bad they didn't do that instead of the ladder LEDs in the other FX pieces that are so prone to damage. And in spite of the reportedly low powered LED, the blade doesn't seem any dimmer that the standard FX (although I don't have one to do a side-by-side comparison, so I can't be absolutely sure).
You know, I've never been a booster for MR or any of their stuff, but I really don't know why everyone seems to be down on this kit. Certainly, it has it's drawbacks, but for the $100 I figure it's well worth the investment. Especially considering the cost of the standard FX sabers, or aftermarket conversions, and then you're stuck with that ONE saber design. Apart from the fixed blade and the limited amount of colors, the kit is infinitely customisable and upgradable.
I bought and returned a Luke ESB, for a variety of reasons, but I think I'll keep this one. If anyone else decides to get one, I'd be interested in their impressions of the kit.