I don't have the 100+. just the regular 100. But from what I can tell, the only differences are the magnets and the firing pin.
So this might not apply.
What part is sticking? The button is 3 pieces. There is the actual button on the circuit board inside, plus the two pieces visible from the outside which are the actual piece you press on and the ring around it (held to the metal box by a nut on the inside). If it is the plastic on the outside that is sticking, then it could possibly be easily fixed with some sandpaper. The large plastic piece can unscrew pretty easily (had it happen to mine a few times from normal usage) and the button piece comes out of the ring easily. Just sand the inside of the ring or the button a little so it isn't such a tight fit then just screw it back down with your fingers. The nut on the inside wont spin freely (but can slide up/down) so it is possible to get it tight with just your fingers by pressing down on the ring while trying to spin it. Make sure to remove the batteries first since you'll be practically pressing on the button and don't want it turning on and firing.
If it's not the plastic piece, then it could be that the switch on the circuit board is defective which can't easily be fixed.
I will say again the above is based purely on my experiences with the normal 100 watt.
But, my coworkers 150 watt appeared to have the exact same button design, so I have to guess the 100+ has it as well.
