LED lighting flicker.

I have some strip LED, 12 Volts, fitted to the 3D Printer to light it up.

Originally I powered these by having them plugged into the RAMPS 1.4 power input which gets it's power from the 24 Volt to 12 Volt buck converter using the Yellow 30 Amp wires.

This caused the LED strip lights to flicker when the hot end temperature reached it's set temperature, I believe this uses PWM once it gets to the requested temperature. It appears as if some of this PWM voltage/signal is passed onto the power input ports on the RAMPS 1.4 casing LED strip lights connected in here to flicker. The LED strip lights would flicker at the same rate and time as the Hot End LED would on the RAMPS 1.4 board.

This was annoying.

I changed the LED strips from using the Yellow wire out and use the Red wire output with the supply using the same 24 Volts input to the Red and the Yellow, on the input side.

This resolved the flicker issue and the LED strip lights and now stable.

So for the 24 Volts to 12 Volt buck converter:-

Input 24 Volts positive to the input side going to both Red input and Yellow input

The 12 Volts outputs Yellow, (high up to 30 Amps), wire going into the RAMPS 1.4, both to the 5 Amp and 11 Amp input on the RAMPS 1.4 board.

The 12 Volts outputs Red, lower Amps), to power the LED strip, and other 12 volt parts.