Too much mains noise on Hantek 5202P

[testtube44]

How do I get rid of the mains hum in the waveform on my oscilloscope? Filter mode does nothing and it's still too intense, I wish there was a strong enough filter on it so I could focus in on stuff I actually want to see. How can I use the filter appropriately? User manual didn't help.

[MrAl]

Hi,

I have no experience with that scope but in general this will happen when there is a bad ground connection in one of the probes.
Just something to check first.