I picked up a broken Istick 50w because, well, I like to fix things and the opportunity presented itself. This unit was suffering from the "low power" error as well, complete with the funny little beep noise when trying to fire. I pulled the unit apart, and have to say, am not a big fan of the perpendicular connected printed circuit boards. Immediately I was suspicious of this connection so i put a little pressure on it while attempting to fire (be very careful if you troubleshoot this way, don't short anything out!) and what do you know, it's started firing! I broke the unit down a little further to get to the back side of this PCB connection and found the cracked solder joints pretty quickly. It was the 4 connections farthest from the firing button/atty connector. These are pretty tight tolerances, so you will need someone experienced at soldering with a fine tip soldering iron and steady hands. Once I re-flowed these 4 connections the unit started functioning like new!