[Elecraft] VFO B problems

[Jacques Gaudron]

Hello everyone
A rather curious phenomenon occured  to my K3 (# 2450) some time ago : 
the VFO B readings display no  more a frequency, but only the main menu 
or the configuration, however I tap or hold the "Menu/Configuration"button.

The VFO B knob is "dead, and does not change the frequency if I check 
with the A/B button. And the second receiver is mute, though it seems to 
connect something when I press "Sub".

Has anyone an idea ?

Thanks for any help...

Jacques de F9OJ

PS  : I found no solution in the abundant configuration menu !