I have a roku 4200X connected to a Samsung TV. When it gets hot outside the roku picture will start to flicker after about an hour of viewing and then totally scramble to black and flickering lines. Only happens in summer when hot outside - inside is always ac controlled to 74. Switching to broadcast TV fixes the picture immediately. Switching back to roku input then goes back normal for a few minutes and problem starts over again. Never happens in winter. I live in Houston and it does get supper hot, but can't figure out how that is affecting the roku or roku picture. Never happens with broadcast TV or DVD. Roku is connected via Ethernet to router just 3 ft away. Have Xfinity high speed internet and not similarly affected on other devices. Just with roku. Has been happening the same way for years... Every hot summer roku starts to flicker after an hour or two of watching and then goes to a full blown scrambled mess. Any ideas?