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Table of Contents
UNDER CONSTRUCTION
Remove Fan PWM Noise
Author: AETEK
The changes shown here require knowledge in the field of electrical engineering and can overwhelm normal users. Also, I would like to point out possible dangers that exist in certain interventions. All adjustments have been checked for function.
Difficulty: Advanced
What is this about?
https://en.wikipedia.org/wiki/Pulse-width_modulation
PWM (Pulse-width-modulation) is a technique with which the performance of e.g. a fan (as in the A5) can be controlled.
As a side effect, noises can be emitted through the fan due to the pulsating current. This refers to noises that cause the propeller to vibrate due to the electric coils. Noise can also have other causes. Worn bearings are often the cause. The PWM filter does not help against this kind of interference noise.
If the fan is mechanically good and there is still noise, then it is the PWM frequency emitted by the fan. The Marlin firmware offers several options to reduce noise by software. I have checked all these options. Unfortunately, hardly anything has changed in the result. That's why I developed this hardware solution. It is specially tailored to the fans of the A5. If you're already there, then you can build the circuit twice. One for the Cold End fan (A5 upper) and one for the component cooling (A5 lower) fan.
Note:
Just as the A5 is delivered from the factory, only the component cooler is PWM controlled. The Cold End Fan is directly connected to 24V. Here the filter can not filter PWM noise. In another post, I show how to regulate the cold end fan via PWM and thus gets quieter. Then the filter helps to prevent PWM noise for the Cold End fan.
Required Electrical Parts (for one fan)
- 1 x Diode 1N 4007
- 1 x Resistor 100 Ohms 3 Watts
- 1 x Electrolytic Capacitor 220uF 35V
- Optional 2-Pin plug and socket for building an plug-in-adapter
- Some cable and heat shrink
The hobbyist will most likely have the parts in the tinker box.
Build The Circuit
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The female pin header is connected to the MKS GEN_L 1.0 mainboard.
The plug belongs to . See photos. Please note the polarity
