An incompatible video signal has been received

[Helles]

My Sharp Aquos tv says incompatible video signal has been received
Only on some channels
Have tried new aerial
Reset factory settings
Nothing else is connected to tv
It has an internal set top box
Could it be the set top box has died

 

[Ralston18]

Is there a pattern to those "some channels"?

Do you see any differences between them and the channels that do work. E.g., Standard definition vs High definition?

Have you checked with your service provider?