I have a Luke ANH Hasbro Force FX Signature removable blade lightsaber that only light up half way. I took it apart and It looks like only two of LEDs of the thirds stage are lighting up.
So I think the next LED of this series (or maybe more) is defective. To test that I would like to find some of those blue LEDs individually or on a strip. If anyone has some of those or has info on them and how to get some, please let me know.