Hello everyone. I’m trying to modify a Chinese XHP70 flashlight purchased on AliExpress so that instead of three operating modes, it only works with one. Could anyone tell me what I should do to achieve this? Thanks and best regards.
I attach a video of the expected result of the same flashlight (at 15:30 minute): https://youtu.be/mXEBbkz3mo0?si=gY5DmyDrW9c-bUtX
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Thank you raccoon
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If it’s a mechanical switch, this will completely negate the driver. Just remove some of the red solder mask with a knife or a small screwdriver and solder the red wire to it.
Connecting directly in this zone which you mention all circuit is avoid? If is like that would be like connect the battery direct to led?
Is it possible to do this without overriding the controller, meaning it can work in one mode with this type of switch? Thanks for the response, colleagues.
OK, so, the part markes “U2” is a hall effect sensor that registeres if the magnet in hte switch is close or not and tells that the IC.
That means, that the fix that I wrote won’t work - well, it will, but the light will be always on.
So, there is really nothing you can do about this, you would have to reprogram the IC and that is basically impossible.
You would need a new driver with a hall effect sensor in the same position
These zero-ohm resistors look interesting, can you track where are they connected? They might be used to configure the driver. Not sure if any combination of them can enable single-mode, though.
I have a bike computer with similar arrangement of four resistors: reordering them has turned it into a more expensive model with more functions 
These resistors are just there to put in some current limitation for other lights with the same driver but LEDs that can’t handle enough current.
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You can remove the U1 controller chip and use the U2 magnetic sensor to activate the Q1 and Q2 transistors that are responsible to light up the LED.
By doing so, the switch behavior might be reversed, meaning that the light will be turned on in the off position, and off in the on position, depending on the default magnet orientation.
Hi TUIG101! Thank you so much for response, It is precisely where I am looking for. Could you tell me what kind of resistor have to put there?
The datasheet says 820Ω, but 1K should work alright. Mind that there’s a seemingly 10K resistor between the gate and the source of the MOSFETs, so if you choose a resistor value that’s too high the MOSFET might not saturate, and these SOT23 MOSFETs cannot dissipate much heat if any at all. Size can be 0805, 0603, or even 0402 if you are crafty enough, but 0603 might be just about the perfect size.
The switch is on when detects that the magnet pass on and off in the same situation, it is a slide switch
Thank you so much, TUIG101. I’ve made the changes you indicated, and the result is essentially what I was looking for. Thanks again. Best regards.