I'm 1/2 way into it and will let you know how it goes. You can grip the inner silver ring with pliers and unscrew it (along with the inner plastic lens). That assembly hold the outer ring on, and reveals that the bright inner led is a standard "star" mounted unit w/ 2 wires soldered on. I've ordered a replacement led ($2) and will find out if replacing it fixes the light.

Here's a video I found that gives some idea of how to disassemble
http://www.youtube.com/watch?v=GdI_vUiN38I