[Elecraft] low IF out on K3

[Enrico Lorenzoni IU3AZC]

hello everyone,
I just compared my k3 with a friend's one and my IF out is much lower 
than his k3.
I suspected it when listening on a softrock, but now I can see a 
difference like 10 or 20db off.

So I inspected my k3 and the IF out connector is fine. Multimeter says 0 
ohms between bnc contacts and P86 pins on motherboard.
What can I check next?
Anyone did fix this same issue?

thanks

Enrico IU4AZC