It does use a star and it is easily accessible. However, changing it may be tricky (Or may not - I'm happy with it the way it is) as the head comes off just below the knurling rather than at its base and the star is recessed nearly an inch in the head which wouuld make soldering the wires onto the star tricky though not impossible. I am in the process of uploading some pics which may help. Since the star is connected by two wires, it may be that it needs to be electrically isolated from the body - a good blob of heatsink compound should see to that.
The star is held on by two screws - it would be a good idea to strongly magnetise your crosshead screwdriver first. The magnets out of old hard drives are excellent for this purpose.
I have a rather pronounced tremor in my hands which I first noticed when I was 12 so have lived with it for 35 years and while it hasn't ever stopped me from doing anything I wanted to (other than TIG welding), it does make fiddly soldering tricky.
This image is with the "head" removed. The reflector just drops out, it isn't glued down or anything
With the reflector out (as well as the focus!) The only reason I left this pic in is that it shows the depth better than the in focus one below.
A nice pic of my knees
I've no idea if it uses any sort of driver circuit or a resistor - I just use it.
I just measured the current draw from it - it is pulling 875mA from the pair of elderly 1600mAh NiMH cells in it which measure 2.58V off-load as I've not the patience to figure out how to measure the voltage under load. This means it is pulling something like 2.58 x 0.875 = 2.26W from the cells, and presumably a bit less being put into the LED.
If you've any more questions I'll do my best to answer them
