Not working - LED strip on FAN 2 header w/ buck converter

  • I have a Duet 2 wifi installed on my Ender 3 which is a 24v system. I purchased these buck

    converters to drop the voltage down to 12v and installed it on fan 2 and added "M106 P2 S1 H-1" to my config.g which adds that fan to the machine control panel with the slider. I soldered up the buck converter and crimped a 2 pin connector and plugged it in to Fan 2 and moved the slider to 100% and regulated the buck converter down to 12.1v but the lights still do not come on. I tested the end of the 3 foot LED strip and I am not losing any voltage as it's still reading 12.1 volts

    Am I missing something? I did read some posts on this forum that were similar but not exact that I would have to add a mosfet inline on the V+ but not sure if this applies to this setup. Would someone be willing to help guide me in the right direction on how I could successfully control the LED strip via Fan 2 header?

    Thanking you in advance


  • Only the ground side should go from the fan connector (duet) to the led. The positive side should go from your power supply to the buck converter and then to the led.

    Buck converters have capacitors on them that wont allow the variable slider to work correctly.

    However the leds should have came on at full brightness with the way you have them hooked up so something else is going on with your wiring.

  • @timcurtis67 I will try moving the V+ to the main power and see what happens. I was thinking the same thing as far as the lights coming on full power with that setup because I have read that the PWM doesn't work properly, but I wasn't able to get anything from the LED strip. Something else going on, like what? It's pretty simple... I have the V+ and ground going to the buck converter (in) and (out) from the buck converter soldered straight to the LED strip. When I get home tonight I will take some photos if that would help any.

  • If you hook the led strip directly to the power supply (with the buck converter installed in between) does the strip light up?

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