Un75nu800d no tuner detected

[vipersinu2]

Hello I have a un75nu800d tv.

Does anybody have an idea why, when I scan for OTA channels; the tv shows channels being found, but when the scan is completed there are no channels saved, and the tv says check your connection.
I went in to mute182 power and the tuner says not detected.

I tested the coax with a 32" Samsung and 69 channel are scanned.

The 32" tv tuner is set to S_T2C, so I tried to set the tuner on the 75" to the same.
When I powerd cycled the 75" and went back to verify the tuner, it goes back to tuner not detected.

Ty