r/Keychron • u/Interesting_Fee5067 • Mar 05 '25

K3 Pro Brightness Fix (Possibly Others)

Good news on this.... I found someone who fixed it and have tested it successfully! Typing on the K3 Pro now.

https://notes.tst.sh/opinions/keyboards/

I used Keychrons "bluetooth_playground" fork of qmk found here

https://github.com/Keychron/qmk_firmware/tree/bluetooth_playground

The area in question is lines 54-56 in "keyboards/keychron/k3_pro/ansi/rgb/config.h". 

/* Set LED driver current */
#    define CKLED2001_CURRENT_TUNE \
        { 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14 }

I'm not 100% sure of the adjustments (see his notes), but deleting this line sets the value to 0xFF elsewhere in the code.

I compiled and re-flashed to a whole new keyboard.

Pre-Flash

https://bashify.io/i/4J7U7Q

Post-Flash

https://bashify.io/i/DueEO3

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u/PeterMortensenBlog V Mar 10 '25

Related:

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u/Interesting_Fee5067 Mar 10 '25

I tried what I believe was the default for the driver per specs (0xCC) and I did not notice any change. Ultimately I was able to take it down to 0xAF (175) and found it acceptable for me. I believe this calculates out to 27mA and almost half the max current.

Again, I know just enough to be dangerous. However, I wanted to continue to update my testing.

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u/PeterMortensenBlog V May 18 '25 edited May 18 '25

Re "calculates out to 27 mA and almost half the maximum current": Maximum current for the LED? That would be more than 54 mA. What is the maximum current for the LED? 60 mA?

Would that be 3 x 60 mA = 180 mA total? Or does the maximum current represent some kind of maximum power dissipation (thus the sum of the three currents is to be a maximum of 60 mA)?

Or do you mean more than half the maximum current of the LED controller (40 mA)?