V10 - Headphone Output issues

Hello,

maybe someone faced this issue or has a solution/answer for it:

No matter what Headphone Channel (A or B) i use, I cannot get any sound out of it!

- Yes: Poti is set on "cue", not "master"

- Firmware 1.12 installed

- Factory reset done

- used different Headphones

Somone got an advice?  Thanks