howdy.
i've taken apart a novatac 120P, as was mentioned in a previous post.
here's how i did it.
take apart the head, battery compartment, and tailcap. you'll have three pieces. the trick is to remove the retaining ring on the inside of the head without damaging too much. if you look inside, against the threaded edges, you will see a ring with two notches opposing each other along the diameter of the ring. you can use hemostats to remove them. a pair of needlenose pliers may work as well. or a pair of calipers. or you can fashion a spanner to get the job done. i've once used a fork, which i cut/bent to accommodate, as a spanner. just some ideas.
once you unscrew the retaining ring, which is probably the trickiest part, the pill will fall out (it's red). then take off the bezel and let the lens drop out, and you'll have your novatac in pieces. makes sense?
if you really need help PM me. i'll give you my phone number and you can call me and i'll walk you through. if it comes to desperate times, you can mail it to me and i'll disassemble it for you no problems.
best of luck.