No sound in left main out channel or too low signal sometimes [Behringer X-AIR - XR18]


Hello everybody. This is Spyros Patras from Athens - Greece.

I have a problem in my XR18 Behringer digital mixer. The problem is that: Most of time i have no sound in the left main channel. Other times i have a very low signal in the left (The right is in 100% and the left in the 15%).

I opened the mixer to find any problem i can see with my eyes (some friend who had the same problem told me that he opened the mixer and put again a cable tape in it's place and it was okay again) but with no luck.

I am working with the left main channel taken from the AUX6 until today but i want to find a solution because i need all my 6 Auxilliary buses again. I tried everything from the X-air edit application such as routing etc.

Do you have any opinion about this ?

Thank you for your time.