There is no need to change any of the circuitry, the drop in <br>"LED pill" is the remarkable easy to use. They give complete instructions, it took me about 5 min. to complete. In a nutshell, here are instructions from the CandlePowerForum:<br><br>1) Unscrew the head assembly, set flashlight aside.<br>2) Pick up head assembly, unscrew the bezel from the head assembly and remove the reflector.<br>3) Laying the bezel top face down with the bezel still inside, drop the o-ring in, then the optics. Screw the base to the bezel carefully keeping the optics centered in the o-ring as it is screwed back together. Set head assembly aside, this part is now done.<br>4) Remove the Lamp and set aside. Carefully pry off the plastic top cap that the lamp plugged into that sometimes says, "Do not remove".<br>5) Remove tail cap and drop out the batteries and plastic insert.<br>6) Drop in module LED first into the battery tube. Drop in the two batteries and screw in tail cap. The module should be blinding you now. This is candle mode.<br>7) Screw back on head all the way down to turn off the flashlight. Backing off the head will turn the flashlight back on. Always turn it at least another 1/4 turn to ensure the module is firmly pressed inside the battery tube.<br>8) Enjoy the light.<br><br>The module will make max. use of batteries and will go to a "moon" mode when the low. A small red LED on the module will come on when the batteries should be changed. This light is great to use those AA batteries that are too low for other lights. Pete