Hi, Just join & 1st post. Have been on the side as visitor for about 1 year but did not sign up as I really am still learning. Back to topic. I have the UltraC5. Got it 4 months ago and used may be a few time each no more than few minutes. Mostly it sits inside my briefcase. Y/day I turned it on as regular check it started to behave funny. Twisted to turn on- it lit up & flicker. Twisting the head a bit further may be 1/8th & more turn causes the light to dim and turn off. Does the same CR123 & 2AA, Tried new set batteries but no change in situation. I open up the head, took out the reflector but the LED module seems permanently fit inside. It does not move at all pushed from either LED or the contact side. I have no idea how this switch works nor do I know how to get to the wiring underneath. Any pointer would be appreciated. Cheers