Box turns off

I have trouble with My Vu+ Uno4k.
After 5-10min it only shows a black screen. The remote doesnt work, cant turn the box off, so i guess its not the tv.
IF i switch on\off at the back it doesnt start Up. I have to remove the Power supply cable and wait 5-10min then it starts Up. But only to switch to black screen After a while.
Feels Like perhaps the box get to warm and switch off.

I have tried to upload latest openVix, same problem.

Its a original, No clone!

What can i try? Can Mount some extra fans in the box IF heat is the problem?

Thanks

The box is still under warranty have a chat with the person who sold you the box