my Samsung TV goes black but still had sound it just started when I got a new cable company. when it happens I reboot the cabl

Shaun o

In the settings menu of the cable box.
You should have the options to set what type of picture aspect the cable box outputs to your Samsung Tv.

It will have an setting of Auto where the aspect of the picture can change depending on the content broadcast via your cable tv box.

But you can set it to a fixed aspect ratio, if the picture is lost on your Samsung tv when the aspect ratio is switched from one to the other when a break in content shown changes due to adverts ect.

Also check that the mode is set to a fixed resolution of 1080p and does not auto change.

It should resolve the problem of the display image on your tv from going off.