Ultrafire C3 Switch



Ultrafire C3



I bought an Ultrafire C3 LED flashlight from China. Many of you in the LED-circle are probably familiar with the C3. Its notoriety is what made me decide to get one. It's a great looking flashlight and not very expensive. When I first received it I was very impressed with the anodyzed aluminum. The threads were cut clean and smooth. I also own a C78 which I reviewed three years ago and that one is not as pretty as this one. The C78 still remains my favorite, though.

Everything would be great until I noticed the switch assembly on the tail cap. The original C3 used a PCB in the tail cap which the switch and spring are soldered onto. This provided a secure and reliable electrical connection. Well, the enterprising Chinese have found a way to ruin a good thing for the sake of lowering production cost. That would be fine if I had been informed upfront. The C3 I received basically has the switch, washer, and spring press-fitted together. My experience with this type of assembly is that the compression can become unreliable over time and result in the ever so common problem of flickering light or a dead light. Even the heat generated by the flashlight can cause the thin metal contacts of the switch to lose positive contact.

Ultrafire C3 tail capUltrafire C3 spring


I took it upon myself to fix the problem and disassembled the switch assembly. I also dissected the switch to showcase the inner-workings. Fortunately, it was easy to take apart without breaking anything. Sooner or later you will have to clean and oil the guts if the switch stops functioning normally. Oxides and other debris accumulate between the contacts and can cause intermittent contact.

Ultrafire C3 switchUltrafire C3 switchUltrafire C3 switch


The way the spring freely moves with respect to the washer made me suspect this was causing the flickering in my light. Twisting the tailcap ever so slightly can cause intermittent connection. To alleviate the problem I soldered the spring to the washer. I would have liked to solder the switch to the washer as well but it probably would have melted. If I can track where to get an original PCB for the switch I would do that replacement instead of this hack.

Ultrafire C3 spring


This appeared to fix the flickering I experienced. Time will tell how it holds up. All threads and contacts are cleaned and lubricated so everyting is functioning as should be. I used silicone oil so it doesn't degrade any plastic or silicone oring.