The player connected via the Onkyo receiver and every time I turn on the Zidoo with the other HDMI channel set, for example satt TV, and only after a while I switch to the appropriate HDMI signal and I need to reset the signal. Not only that, if I leave Zidoo turned on and switch to another source, sometimes it does not detect the signal when I come back. What could be the reason?
ad1 Yes, in the same way, the signal is only when I turn on the same channel in which the player is connected. ad2 I'll try, but always my cable was good. With other box.
So if seems to be better i would suggest You to connect your box straight to the tv and check how it behave on each cable... If still wrong I would think that something could be wrong with av receiver.
Dorszes is correct I think, I had a similar issue, when I turned my X9S on for the first time the TV indicated "No Signal" which was quite a scare since I had just got it but when I switched cables it worked with no problem! I'm not sure exactly what the deal was since the HDMI Cable (that didn't work with the X9S) was working fine with my old android box (x96 Pro) my guess is that HDMI cables have been improved over the years and perhaps it was somehow not compatible with the X9S much like a USB 2.0 cable is not the same as a USB 1.0 cable
Lot of missing info in your post. For exemple if you have a 4K tv if you hook your Zidoo box and Zidoo is set to auto resolution, the EDID will be pass from TV to Zidoo resulting in 2160p 60hz signal. But if your cable is not HDMI 2.0 18Gbps, the TV will not be able to display via HDMI 1.4 cable. All depend of your setup, also sometime no signal can happen specialy with HDCP 2.0 link with HDCP 1.0... Even if it compatible I found lot of case of "mistmatch" in such config.