Hi there party people

I have bought 3 ceiling fans with a light built-in. The problem is the light has both cool white and warm white LEDs. When switching on, it first goes to warm, then cool, then combined, then back to warm. I want to deactivate the cool white lights so if power is sent to the light, it always and only turns on the warm white lights.

I don't want to waste money on a new LED and am keen on a little project.

Please see the light / circuit board attached.

I've also included what I think I need to do, but I am a COMPLETE noob, so it's really just a guess:

1. I think the red arrow is where it is being controlled by. That seems to be the point it splits between "w" (which I assume is white) and "y" (which I presume is yellow)
2. So if I remove that black thing (sorry, don't know the correct term) and solder directly as per the red line?

Thanks in advance for any advice

 

Welcome to AAC.

While it sounds/looks like you could do what you want, we really need the part number from U1—the component indicated with the red arrow—before we can help without guessing.

 

Welcome to AAC.

While it sounds/looks like you could do what you want, we really need the part number from U1—the component indicated with the red arrow—before we can help without guessing.

Thanks for the reply. Please see attached. I'm worried that is not clear enough?

 

it is not

 

It might possibly be that ultraviolet illumination would better display the markings. And it may also be that sommebody has a display that can provide greater contrast than what I have on my screen.

As an alternative, if there are different LEDs for the different colors of white, then covering the ones you do not choose could be a simple option.

 

It might possibly be that ultraviolet illumination would better display the markings. And it may also be that sommebody has a display that can provide greater contrast than what I have on my screen.

As an alternative, if there are different LEDs for the different colors of white, then covering the ones you do not choose could be a simple option.

The only problem is that the circuit goes through three modes: warm white, cool white, both. The TS wants the switch to do nothing (effectively) the result always being warm white.

The chip in question appears to be a multi MOSFET package (either two or four devices). In the absence of a datasheet, my surmise is that the trace that connects the two pins from the package to the cool white LEDs could be cut and the output from those two pins be combined with the two pins that current go to the warm white LEDs.

This is speculative, but I thnk it is correct. However, without a schematic I don’t have enough confidence in that answer to suggest it.

 

another option will be to somehow get more of those warm white LEDs and replace all of the cool white ones with warm white.

 

the LEDs seem to alternate. so cutting trace between drain of MOSFET that activates cold LEDs would disable the cold LEDs.
optionally also soldering wire from drain of that mosfet to drain of warm LED mosfet would make a wired OR circuit.
You can always reverse the change by removing the bridge and placing it across cut. That is unless something goes wrong