Chromecast not working at all

So, today I bought a Chromecast (2. Gen). At home, I connected it to my TV (Sony Bravia KDL 40EX727) and tried to set up - but without success. All I got was a black screen (nothing appeared at all). At the Chromecast itself, directly after plugging ac power, the status led turns constant organge for about 0.5 sec and then switches to constant white. And that's it.

I started to research and found some points I struggle about:
- Some users reported unresolved issues with Sony TVs. Can I find a list of supported devices somewhere?
- I tried to reset my Chromecast. I followed the instructions (push the reset button while HDMI is plugged in the TV). Actually, nothing happened. The LED keeps on illuminating constantly white (still not blinking). Google's instructions tell me, that it should turn orange (blinking) and after the successfull reset it should return to a white color. So as you see, nothing at all happens.
- I tried all HDMI ports - no difference
- I tried different USB cables and powering it from USB and from AC - no difference
- I tried turning it on without beeing connected and with beeing connected - no difference.

What else to do?
- tomorrow, I will take it to work and connect it the HDMI port and my computers display (unfortunately, I have no second screen with HDMI at home, neither an adapter from DVI to HDMI or something similar..)

Do you have any hints for? Or is my device just broken?

Thanks in advance!