Whatsminer M21S Fan Speeds increased by 2k

[ltk6260]

Hi forum, does anyone have any experience with whatsminer M21s fan speeds? I've been running my miner in low power mode, for about 9 months without issue, auto fan speeds were stable at about 4500RPM. For the past month, the fan speeds have been stable at 6200RPM.
No change in the environment, ambient temperature, or board temperatures (~55, 59, 64c). I checked the fans, nothing blocking intake or exhaust fan and have restarted the unit. After its normal 5 minute startup cycle the fans slowly climb up to about 6200 RPM and stay there.

Any suggestions?

[GFDhd]

I wonder if you solved this problem later? Normally, Whatsminer's M21S fan can up to about 7000 RPM, so 6200 RPM is not too high. It may be that the voltage or current of your power supply has changed at that time, so the speed has increased. If you want to keep it at 4500 RPM, I think you can choose to replace the lower-performance fan or use a voltage regulator.