[Elecraft] K3 Squelch

[N2ZDB at aol.com]

Hello K3 Users,
 
I am trying to figure out how to set up the squelch and currently have SQ  
MAIN = Sub Pot.  When I rotate the RF/ SQL SUB dial I get a "SQL N/A"  
message that pops up and goes away.
 
Any idea why this is coming up and the squelch does not work???
 
Thank you,
 
Michael
n2zdb