[Elecraft] K3s Notch Filter

[Bernie and Cheryl]

Dear Folks:

I have a question about use of the Notch filter on my K3s.  I am 
primarily a CW operator.  I understand that, in CW mode, the notch 
filter's operation is manual, and you tune (adjust?) the filter using 
the VFO B knob (admittedly, I've not tried it in USB or LSB mode, where 
I understand its operation is automatic, unless you opt out).

I have tried using the filter in CW mode and can detect no effect 
whatsoever while turning the VFO B knob.  I even tried it on the AM 
broadcast band, with the rig in CW mode, and was unable to have any 
effect on the AM carrier.  For what it is worth, the little indicator on 
the LCD display, with the two arrows, does come on when I press the 
Notch filter button.

What am I doing wrong?  Thanks for any help you can give me.

73 de Bernie, KF0QS