Electronics go bad. Sometime the first week most times sometimes soon thereafter.
Cables go bad too especially HDMI.
I replaced a Sony TV and soon thereafter I would get green screens on a different TV. There is this whole hand shake that HDMI must do to verify all devices that are connected.
So, first think I would do is disconnect power from ALL the TVs and all TV receiver boxes and any and all HDMI splitter devices. Then supply power and turn on the TVs. Then the HDMI splitters then finally the receiver. If that doesn't work you can try and swap out cables (probably way too hard to do. And then swap out the HDMI splitter.
In the end my HDMI splitter failed and I put in a better quality one and all has been fine for months now.
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