[Kenwood] 160m reception?

[WW3S]

I'm wondering if I have a problem with my TS850 on 160m? The noise level is
always 20 over 9 and obviously I can only copy the strongest stations. It
may just be powerline noise but here is what I see; when I tune down into
the broadcast band, the noise disappears or at least diminishes. I know the
radio as a attenuator in that portion of the band so that makes sense but
when I tune above 2.000, the noise also is cut way down. I can hear
something click ( the bandpass filters I think) in as I tune from 1.999 to
2.001 and whatever happens really cuts the noise way down. Is it possible
something is wrong with the filtering in the 160m portion of the bandpass
filters? How can I check it?