Try power off to the Chromecast, the unplug it, then power off the RCA then unplug the mains (AC) cord for a few minutes, plug in the mains, then your Chromecast then retest.
Now for the upsetting part. The cure is to change the model HDMI chips but no make does that. We end up changing the TV or the device. Since the Chromecast is not on some HDMI cable, that's not a factor.
I have a RCA SLD65 that "blacks out" (sound still plays) while watching Netflix via a Chromecast HDMI connection. Does anyone else experience this and can anyone tell me how to remedy this? It is aggravating!