I killed mine changing the LED out. I asked 4Sevens about a replacement and they said there are none.
So I converted it to direct drive. I picked out a Cree XR-E that would run under 2 amps on a fresh battery. It settles down to less than that after a few minutes of course.
I kept the two stage capability of the light. When the head of the light is unscrewed slightly an LED - wire goes through a resistor to the brass body of the pill to complete the circuit. That is the low level, just like stock. To put it in DD I gutted everything off the old driver board and soldered another LED - wire to the negative ring on the bottom side of the old driver board that makes contact with the body when the head is screwed down all the way. So when the head is twisted all the way down the light receives full amperage from the battery. Very bright. The LED + wire is soldered to the center nub that is connected to the spring.
It's dependable now. No driver to fry.
I have a 25 Ohm resistor in it right now, but I'm going to change to a 50 ohm to get the low lower.
Edit: I'll try to add some pics tomorrow. The light is easy to take apart. The mod was easy, but finding an LED with just the right front voltage can be tricky. You need an assortment to pick from. Some of mine had too much current flowing through them in DD, and some were a little on the low side.
