Q2-2SM. When I switch from low to high there is a gap of about half a turn when the light shuts off. Quite often when I leave the light on high next time I want to fire it up nothing hapens and I have to tighten or loosen the head to make it work. I sent Alan an e-mail about it and he told me to "clean the pill, rear of the reflector, clean the inner of the conductive surface in head, then install them back". I tried it several times and even ordered deoxit and tried with that but the probem remains. I just sent Alan a new e-mail about it but want to ask you all if anyone has any suggestions.