[Elecraft] Bad crystal filter ?

[James C. Hall, MD]

Working with my newly constructed K3S today, I noticed that receiving through the FL4 crystal filter (400 hz, 8-pole) was noticeably suppressed. Through the FL3 (1.8 kHz) filter, an RTTY signal would be nice and strong with good S-meter indications. Going to 400 Hz the signal would nearly be lost and I could not decode it. Going to FL5 (250 Hz), the S-meter would pick up again with strong signals.

There's not much to check on the Config menu except the FL4 GN and it's at max (8 db) - not much change. 

Is there something else I should do to deal with this ?

73, Jamie
WB4YDL 

Sent from my iPad