Troubleshooting ideas?

[raz]

Working on an Ultrafire CREE light that has stopped working; currently I'm out of ideas. The light will operate as advertised with tailcap jumpered into circuit; once I screw tailcap onto rest of light body, the light no longer operates (I can see one/several sections of emitter quadrant lit dimly/flickering). So far I've:

• checked clicky switch using continuity check; all seems well
• removed a coil from tailcap spring as I suspected it may be compressing too far, spreading out and shorting light
• cleaned all threads thoroughly with deoxit
• cleaned and lubed O rings

So far, no joy. As I said, the light works with tailcap jumpered to rest of light body; once I install tail cap on to body = inoperative. All thoughts appreciated!

 

[AnAppleSnail]

Tighten the ring in the tailcap?

 

[gadget_lover]

The flickering segments point to very low voltage. This can be caused by an open or a short.

The tailcap is supposed to connect the bottom of the battery to the case of the light. We can call that 'ground' If it is doing that successfully you need to look at the other end.

The other end (head) of my Ultrafire (wf-502b???) has a spring and a circuit board at the Positive terminal of the battery. It also has some lumps of solder that might be connected to ground.

It sounds like your battery may be shorting out when pushed all the way down by the force of the tailcap spring. You can test that by shorting the end of the battery to the battery tube, then pushing down on the battery.

The other possibility is a bad ground at the head of the light. Mine uses a spring to connect the battery tube to the head's electronics. It's soldered to the circuit board.

Dan

 

[raz]

Good tips and thanx for replies. The tailcap ring is good and tight; I'm shifting my focus to the head of the light to look for shorts/opens.