Hi

My DSL 20 HR is completely silent when effect loop is in standard active setting. 
No sound goes through. Only a very very silent cracking. 
when I switch the effect look off to bypass via the foot switch, the amp will give out the regular sound, of course without any pedals that are in the loop

i ruled out broken chords. It is the same without anything in the effect loop at all. 

any suggestions?

thanks a lot