Unsolved Stepper motor hum on one machine but not 2nd one.

[Mr.T2U]

I have two identically built machines sourced from some BitsforBytes printers. Both are cartesian, and I've been running a Duet 2 WiFi with version 3.1.1 on one for a while. Just got another WiFi board and upgraded that one to 3.2.2.

Both have the default 16x micro stepping with interpolation enabled as I essentially copied the config files from one to the other.

Yet, I've noticed that my 1st machine with 3.1.1 is insanely quiet but the printer's steppers with the new board with 3.2.2 have a slight hum when moving. It's still better than when running RAMPS, but it's been death by google and searching through the Duet3D forums trying to find any settings, motor tuning, or anything else I should look at to understand why one printer is making a little more noise.

Belts are similarly tensioned and for sure both X & Y motors on the 2nd printer with the new board are making the hum.

TIA for any input/suggestions.

[Alex.cr]

@mr-t2u

I have a very similar machine, a Cube Pro. In my case the only motor that hums really badly is the nema 23 z axis stepper.

Have you verified the motors are the exact same between machines? I heard that 3DS screwed with the supplier base when they acquired BFB.

[Mr.T2U]

@alex-cr, thx for the response and AFAIK, the X & Y motors are essentially the same. I can hear it coming from the X motor and the dual Y motors. So too coincidental to be all three.