Hello all,
I just finished soldering a new qlite driver for a p60 flashlight, and I seem to have done something to the driver so that now it is only single mode. Does anyone know what I might have done to cause this to happen? Initially, I soldered the board in and tested it (no problem), but the stock spring was too short for my unprotected cells to connect, so I replaced the spring, and now there’s only one mode. What should I do?
Black wire shorted to ground.
Do you think you might have overheated it? The MCU is directly under the spring.
Extremely unlikely. The only way to get that to happen by messing with the MCU is if pin 6 gets shorted to BAT+, and I don't know how you do that without also affecting the rest of the board in a way that no light comes out at all.
Always check the most likely cause first, it saves time. Imagine starting your checks with the most unlikely, then working your way back to the simple ones...
I don’t think I overheated it. If the black wire shorted, can I do something to get the modes back, or are they gone forever? :_(
A 7135 driver works by restricting current flow between the black wire connected to LED- and ground. If you short the black wire to ground, it bypasses all the 7135s and the MCU and everything else, and it runs in direct drive. BAT+ is always connected straight to LED+ on the red wire.
Is it still 1 mode with the reflector removed?
Measure ohms from the LED- solder pad on the star to ground on the side of the pill.
Un-ground whatever is grounding the LED- leg of the circuit and it will work again.
The modes should come back if you fix the short. Most likely a short to the reflector.
Thanks guys for the help and ideas! I can’t do anything right now, but I will try all this stuff tomorrow. I appreciate it!
If the black wire is shorted to ground either by the reflector or on the driver you will get single mode unregulated direct drive(driver board is bypassed). If the red wire is shorted on the driver to one of the 7135 input pins you will get single mode regulated(7135 chips still control current but short bypasses processor fixing current on high). One way to tell which it is is to measure tailcap current. A black wire short might result in current higher than spec while the red wire short should be nominal.
It was, in fact a negative short to the reflector. All fixed now. Thanks guys!