Tv switches Input after installing Q5?

[MrDist]

(It might be a few spelling errors, sorry about that! )

Hi, I recently bought a Q5 unit and my setup is HDMI1=setup box for terrestal channels and HDMI2 Himedia Q5

So the troubble is that when the HDMI cable is connected to the Q5 and the box is either  STANDBY or even if the powercord is out the tv go black for a second and the HDMI1 osd comes up, this happens about every 15-30 sec...

When the box is ON theres no problem watching HDMI1.

And I had a blueray player connected to HDMI2 for years without any problems.

Ideas? 
Thanks!