Roku doesn't manufacture "Roku TV" sets, it only supplies the Roku operating system. This sounds like a hardware issue that needs to be referred to the manufacturer of the set.
Manufacturer support contacts for Roku TVs: https://community.roku.com/t5/Manufacturer-Support-Warranty-Resources/Contacting-Support-for-Your-Ro...
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
If this post solves your problem please help others find this answer by clicking "Accept as Solution.".
Ultra 4800 | Streaming Stick 4K+ 3821 | TCL Roku TV 43S245/C107X