[Elecraft] K3: NB says "IF N/A"

[Frank R. Oppedijk]

Hi,

While participating today in the HA DX contest, I tried to reduce a 
kind of ignition noise. I switched on the noise blanker and noticed 
that I could only adjust the DSP NB; the second line said "IF N/A". I 
am sure this worked some time ago, but as I don't regularly use the 
noise blanker, I can't say at which moment it stopped working...

Has anyone experienced this before? Did I screw up some config 
setting, or is this a hardware issue?

Thanks in advance, 73

Frank PA4N