how to identify problem ? astrolux c8

hi everybody, i recently received an extension tube for a convoy c8 which i thought would work in my astrolux c8.

when i got it on using two button top protected 10amp baterries it wouldnt light but as i was unscrewing the head (switch was in on) it gave a few flashes, tried to light up as if it was making contact....

removed the extension tube, threw in the usual samsung unprotected baterry but it wouldnt work.

removed the reflector, turned the switch on, measured volts in the red and black soldered cables next to the led and i got 4.1v just like the baterry....

used the same to cables to read diode reading (dont know if thats the way to do it....) and i got OL reading, meaning the led it ok....

can someone suggest what might the problem be ?

thanks

Screw the head firm onto the body. Remove the tailcap. Drop in a battery.
Use a piece of wire to connect the bottom of the battery to the bare end of the body.
Does it light up?

The driver cannot handle 2S probably and is now dead. And the LED as well if you read the battery voltage at the LED.

hi, i did as you said, connected wire to flashlight body, no light....

does this mean led is dead ? board is fried ?

i thought the c8 can handle two batteries...

Stock C8 driver is 4.2v input for a single li-ion, not two. Unless it’s a buck driver, 2 batteries will kill the driver. You’re lucky if it didn’t kill the led as well. You can test the led with your multimeter in diode test mode to see if it’s survived.

i did that but without unsoldering it, in diode mode the multimeter displayed OL which i think means its ok, correct ?

or i have to unsolder the led first ?

I have similar in a new unused divers Torch, Sofurn SD03.
Battery fine. (Samsung 30Q/ Panasonic B)
Tail off. Current through Body/led.Battery.
Fine. But no shine.
Lens end off, exposing LED and red/black solder joints exposed.

Multi showing 4.2v, current through torch from red to black wires on board
either side of LED which shows normal colour (No burn)
but NO led shine.

It’s too much hassle making movie of and sending to China for wty.
Old Fart.(I have noo idea how)
Rather just buy a led and mounting board, then
get granddaughter to solder on for me.
Opinions please.and sorry for sticking nose in but same subject.

Unless a driver is specifically listed as able to take multiple cells, assume it doesn’t and can’t.

I once bought a 1-mode drop-in that was rated “3-20V”, but when I put in a pair of 18350s, the LED instantly went blue and dim.

The “driver” only had a stack of parallelled resistors as “regulation”, and that was the only thing that kept the LED from acting like a fuse.

Luckily I only had it on for a second or two before instantly disconnecting it, and back to a single cell it still worked okay, so I kept it as a kick-around light.

Any driver that has any smarts to it (µC, regulator chips, anything), and it’s dead. Dead, dead, dead.

Unsolder the driver wires before doing the test. You should see the led light up or at least the multimeter will display a voltage value (around 3 volts). If it’s dead, it won’t show anything. Make sure you observe polarity.

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