I'm basically dead tired on fiddling with this problem. Let me start with the beginning.
I got myself an RPi 2 (the one with the quad-core CPU) for my media center project. As soon as I got it, everything went according to my plan: I loaded up openelec 6.0.0 on an 8 GB SD card (Hama, class 10), I connected the Pi to my Samsung UE65H6400 LED TV, network plugged in and booted it. All was awesome, the OS was running smoothly, I configured my Kodi Isengard how I liked it, with samba shares from my desktop running flawlessly. I also connected to it a wireless Microsoft keyboard and a Trust MCE remote I used with my desktop. Everything is great, I can basically control the Pi with all the remotes on my livingroom table (this was a complete surprise, I didn't know about CEC and it left me speechless for a while, like wtf is happening, how did I do this - awesome stuff).
But a few minutes after booting the Pi, the screen starts to flicker. Every 30-40 seconds, it's like the TV loses the signal and gets it back after 2 seconds. Total blackout for 2 seconds, audio and video. And it gets worse as time goes, 10-15 minutes into the uptime, the blackouts are a few seconds apart. At first, I suspected the power source for the Pi and I switched it with everything around - my smartphone charger, another USB charger and final, a Galaxy Tab 2 charger with confirmed 2A output - the problem is still there. Ok, it must be the HDMI cable, then. I went and got an expensive, gold plated connectors, high speed, ethernet, fancy HDMI cable and I was convinced that would do the trick. Nope. Still flickering.
Then I got into the configuration files. I tried everything I found. hdmi_safe=1, still not working. Boosting the HDMI signal with config_hdmi_boost up to 11, still not working. hdmi_drive, hdmi_group, the hotplug thingy, none is working. Anything I do, the screen flickers unbothered.
The thing is, after a while, I connected the Pi to an older TV I have, also Samsung, but LCD and much smaller, 32”. I haven't had a chance to test a movie file on it (it's far away from the router), but while in the menus, the screen doesn't flicker on this one.
So the question is this: could it be that the TV I'm trying to use the Pi on is too large for the signal strength the Pi is capable of? If you ask me, that would be absurd - the Pi puts out image at the same resolution, it doesn't matter if that image is posted on a 10” screen or a 100” screen, as long as it's the same resolution, right? But then, why isn't it working?
The next thing I think I'll do is to fiddle with the service menu of the TV and see if I can somehow modify the HDMI input parameters, maybe I can find something that helps it hold on to the signal better.
But in the meantime, has anybody else had the problem I'm having?