There are instructions on the TCSS forums for taking that saber apart to replace it with a conversion kit that uses just a single LED in the hilt to light up the blade...
ANH version:
07-08 MR and HFX Vader ANH - Disassembly only, kits available
TESB Version:
05 MR Vader - Done & kits available
However those same instructions can be used to see how to remove the blade as well as the electronics inside of it. I've done the conversion myself on the ANH version. It can be a pain but it's doable. You may find that one of the top thumb screws on the outside of the saber, the dull metal looking one, may be glued in tightly and may get a bit chewed up trying to get it to break free. Also there are pins in the blade itself, holding the electronics in, that will have to be removed using a small punch or nail. I hope that helps.