I think you have to test it with just the Roku or the source direct to the TV to tell. My bet is at that number of years, it's the TV.
have a HW-N550/ZA soundbar. I connected my Roku to the soundbar. My TV is a 9 year-old Vizio that is connected to the soundbar with a HDMI cord. I use Hulu for Live TV use Amazon Prime as well.
Every ten minutes or so, my TV will turn a hazy blue, then show static, then turn back to hazy blue, and then back to the original picture. This lasts for about 15 seconds. While this is going on whatever I am watching is still playing (I can hear the volume fine).
Is this because 1) my internet connection - I would not think so because the Roku is still working, 2) my TV is older and can not keep up with the streaming, or 3) something else?
Any help is appreciated.