Solution: Switch the HDMI port.
The rambling:
I have Roku 3 and an LG LED TV. I started noticing that when I switched the input from TV to Roku, the screen started dimming in a few seconds. I didn't even need to open any app; it was happening on the Roku home screen itself. My TV has two HDMI ports and I had connected Roku to HDMI 2. Changing from HDMI 2 to HDMI 1 helped solve this problem for me. Prior to switching from HDMI 2 port to HDMI 1 port, I tried tweaking the picture settings in my TV and also did a factory reset of Roku and these did not help. Switching to port 1 is the only thing that worked!
The rambling:
I have Roku 3 and an LG LED TV. I started noticing that when I switched the input from TV to Roku, the screen started dimming in a few seconds. I didn't even need to open any app; it was happening on the Roku home screen itself. My TV has two HDMI ports and I had connected Roku to HDMI 2. Changing from HDMI 2 to HDMI 1 helped solve this problem for me. Prior to switching from HDMI 2 port to HDMI 1 port, I tried tweaking the picture settings in my TV and also did a factory reset of Roku and these did not help. Switching to port 1 is the only thing that worked!
