1W AA LED torch problem

I recently bought a cheap 1W LED torch from china, and after i'd had it a week, i dropped it and ever since it stopped working.
It will flash on/off if i turn it on or off.

So i took it apart and tested it, the switch works fine, and the LED seems to work (it will flash as it makes contact). I don't understand how the LED circuit is working though.

On the actual LED board, it has 4 terminals (2 +ve, 2 -ve).
The positive is connected to the internal circuit (has a capacitor and 2 resistors, and what looks like a transistor).
The negative is connected to the other side of this circuit.

The bit i don't understand, is the second negative terminal on the LED board has a thin piece of stripped wire that sits under the LED board (makes contact with the torch case). Surely this just bypasses the internal circuit?

The torch will only work (light up almost constantly) if this piece of wire is *loosely* touching the case/-ve. If i hold this wire on the case with my finger, the LED will just flash or won't light up at all.

Anyone have any ideas what it could be?

Thanks

Cheap construction. Probably busted the ground (or negative battery) wire loose from the board. BTW, I would think that light runs the -bat from the tailcap spring up through the body.

Solution: Buy MTE or Ultrafire from dealextreme for a very decent cheap light. I have dropped both my MTE and UF many many times with no ill effects. (Hopefully I'll be getting a fenix or SF G2L soon!!)

Throw it out and buy a Fenix LoD CE

Yeh it is a poor construction, and i'll probably get another more 'expensive' one from DX, but i really want to figure out what's wrong with it. :devil:

This is a pic of the inward facing side of the LED enclosure, the end that faces the battery.


removing that PCB, you can see the internal circuit (the capacitor leg sticks through to connect to the +ve nib of the AA.



At the other end of the LED enclosure is the LED, the two green wires are +ve and -ve from the internal circuit. But the negative terminal of the LED (closest to us) is also connected to that piece of exposed wire core, that used to sit between the LED board and the metal underneath.





Buck -- is http://www.dealextreme.com/details.dx/sku.4452 this the torch you have?
I'm kinda put off by the price of fenix torches

Nope, it would probably be easier to get an extention tube than the one I have. I have http://www.dealextreme.com/details.dx/sku.1892. Its actually a great little light, and with http://www.dealextreme.com/details.dx/sku.4735 and http://www.dealextreme.com/details.dx/sku.2394 its almost as bright as my http://www.dealextreme.com/details.dx/sku.6162 (freaking GREAT light, I just hate the multiple modes).

Like I said, with the extention tube on that C3, it really opens up the light output and modding. The board I put in with my Q5 will accept under 1V to a little over 4V. Would be very nice to shove two AA's behind it, but as it stands I'll have to go 14500 li-ion to see that type of voltage in my light.


But I've been very pleased with the Ultrafire and the rebel. Really, the Ultrafire is worth way more than $13. Used it as a commuting bike light all summer, I'd get about a week's worth of useage out of 1 AA battery. Thats typically 15-20 miles a day (home -> work -> home -> GF -> home) with about 5-10 of those miles after dark each day (so like 15-30min useage a day).

The MTE rebel is much brighter, but the runtime sucks, with a capitol S. ABout 30min of a good bright high, but after that it falls off quick; much worse in cold weather too.

That Q5 has got a great tint also. I might end up sticking a e2 lithium in there and putting it in my glovebox if I ever get this goddamned firebird fixed up (frame horn is wasted, gotta figured out how to mount the bumper and get it sectioned on the cheap)...



Edit: The rebel I have draws about 3A from a NiMH battery. The UF with the P4 and board was drwing about 1A on a NiMH and .5 on alkies. With the Q5 and new board its drawing a little over 1A with any battery. Regulation *seems* a little better, but I'm not very sure.