Nasty Cold solder joints... After having my setup get worse and worse for power going on/off (incoming power was good, as the LED was always on), I finally tore it apart today. Turned out to be a cold solder joint right on the PCB to the output power lead. For those that don't know what a cold solder joint is, it is basically that one part was heated enough to flow the solder (the PCB instead of the wire in this case), but the joining part was not, so the solder just filled around the joined part instead of melting the solder onto both parts and forming the joint. Easy fix, clean off the old solder, correctly re-solder!