RGB 3.9 Red LED stays on with power off

MountainSabers · March 29, 2026, 4:14pm

Hello all. I ran into an issue with an in hilt RGB with a 3.9 board. Red light stays illumunated when power is off, but still flashes and functions while in power on mode. It just wont turn off. I have also tried a second 3.9 board with the same exact setup…same outcome…and then on a 2.2 board with NO issues. I have video and a config to share. But the blade array is the typical set for the RGB led. I though nothing of it since it always worked with 2.2 boards for me, but i never needed to install to a 3.9 till now. I simplifed the styles with no luck, even went back to Original sounds and simple styles, I tried other OS’s, and nothing changed. A bit longer into the investigation the Blue LED started to show its color but very dim. My wiring is is fine and from the manual, so i feel there are no issues there. And this also happened on both 3.9 boards only. The 2.2 works just fine with regular styles, colors, and effects and all lights go off with power off. Any ideas? Thanks in advance.

The Blade Array I’m using.

BladeConfig blades[] = {
 { 0, SimpleBladePtr<CreeXPE2RedTemplate<1000>, CreeXPE2GreenTemplate<0>, CreeXPE2BlueTemplate<240>, NoLED, bladePowerPin1, bladePowerPin2, bladePowerPin3, -1>(), CONFIGARRAY(presets) },
};

profezzorn · March 30, 2026, 7:16am

So, when the blade is off, ProffieOS relies on pulldown resistors to turn the FETs off, and it kind of sounds like that is not working in this case.

There is some code we can try to change to fix that if you’re up for it, but this just sounds like the board is made with bad components. Where did you get it?

MountainSabers · March 30, 2026, 2:10pm

Im down to try anything at this point. I have a lot of them. Pixel setups work fine with these. Let me know how you want me to proceed.

profezzorn · March 31, 2026, 4:33am

You can try commenting out this line:

github.com

profezzorn/ProffieOS/blob/5ce0b1351cc4ac916bf95cc997f0b2a8e76ed04f/blades/simple_blade.h#L209


      
          }
          void set(int led, Color16 c) override {
            leds_[led]->set(c);
          }
          
          void set_overdrive(int led, Color16 c) override {
            leds_[led]->set_overdrive(c);
          }
          
          void allow_disable() override {
            if (!on_) Power(false);
          }
          virtual void SetStyle(BladeStyle* style) {
            Power(true);
            AbstractBlade::SetStyle(style);
          }
          
          // SaberBase implementation
          void SB_IsOn(bool *on) override {
            if (on_ || power_) *on = true;
          }

If that helps, I can work up a better solution.

MountainSabers · April 1, 2026, 12:05am

Code didn’t work. Sorry for the picture but I don’t know how else to explain it. If you’d like to continue to help me , I’d appreciate that , but if you don’t have the time that’s okay too I just went back to a 2.2 board , because it works. I’m not sure if anybody else is having the same issue. I am , but I would definitely like to resolve this.

And i’m in no rush , because I don’t plan on doing any r g b anytime soon.

profezzorn · April 2, 2026, 7:25am

No worries, nobody reads the rules, so I usually have to remind everybody, at least once.

Do you have a multimeter with a pointy enough probe to measure the voltage at the FET control pin?

MountainSabers · April 2, 2026, 10:00am

If we all followed the rules , we wouldn’t get anywhere. LoL. But…Understood. Of course , I have a multi meter to be able to test small parts. Need the info on what to test. And maybe if you have a few more suggestions on top of that, id like to try a few at a time. I am capable of multitasking.

profezzorn · April 3, 2026, 5:35pm

This page:
ProffieOS Documentation: How to test a FET

Describes how to measure the voltage at the FET gate.