Siglent SDM3045X power supply buzzing

[hammy]

Hi

any other SDM3045X owners out there?
The power supply of my device is constantly humming, even if it is turned off.
I'm just asking out of curiosity. Maybe I got a lemon. 

Cheers
hammy

[hammy]

I know different techniques to get rid of it.

- Soaking the windings of a transformet with superglue
- Soaking the stacked metal core U-pieces with superglue
- Cable-tie around the windings and/or the metal core
- Hot-Glue for coils
- foam rubber

Any other ideas/tips/tricks? 

Cheers
hammy

[Rasz]

its siglent, probably some rust fell on the pcb and now hums sailor songs

[hammy]

 
It doesn't look that bad. 
I like the features, and the big display. Ok, my 34401A is another weight class, but the histogram and trend chart are nice features in a DMM for that price.

[tautech]

It doesn't look that bad. 
I like the features, and the big display. Ok, my 34401A is another weight class, but the histogram and trend chart are nice features in a DMM for that price.

I'm glad you like it hammy.

Yes they do hum, thay have an always on linear PSU and a soft switch type On button.
One I checked before placing this post, I can hear the transformer from ~100mm away.
The demo unit that I've had for nearly 2 years I've never noticed any transformer noise and yours is the first mention I seen of any Siglent SDM3*** PSU hum.

[hammy]

Yes they do hum, thay have an always on linear PSU and a soft switch type On button.
One I checked before placing this post, I can hear the transformer from ~100mm away.

@tautech: Thank you for the cross reference

Today I had a look inside.  The transformer ist screwed directly to the case. I put a 2mm foam rubber between transformer and case and now the noise is gone. 

Beside this:
- no rust inside
- the smd soldering looks very good
- the internal layout/floorplan is well made

I don't know if such transformers are only tested with 110V/60hz and Germany with 230V/50Hz is a corner case. 

Cheers
hammy