The symptom. My LG 4K TV switch off by going into standby mode. Just as if someone had pressed the power-off button on the TV remote. The TV remote, however is not anywhere near any person or animal - it's lying in full view on the side table. The Roku remote is also untouched next to the TV remote.
This happens repeatedly, but not with a specific frequency. Sometimes as close together as 10-15 minutes, sometimes an entire evening may pass without it happening.
There are 3 actors in this problem: My Roku Premiere+ (4630x, Software version 7.7.0 Build 4154-29); the LG 4K TV (Sept 2015 model 60UF7300); lastly the Roku app for Tablo, an OTA streaming device.
Network connection is wireless from a Google OnHub TP-Link with 802.11ac. [color=#000000][font=Helvetica, Arial, sans-serif]A Roku speed test shows it getting between 23-31 Mbps throughput.Never lower than 23, mostly around the 30 Mbps to the Speedtest servers.[/font][/color]
[color=#000000][font=Helvetica, Arial, sans-serif]One more data point. Today, when it happened, I was sitting in a position where I could see the Roku and the white light on it. Right before it started happening, the white light started flashing and it continued to flash rapidly, but not in a recognizable pattern for 15-20 seconds after the TV had gone into standby mode. [/font][/color]
- The Tablo does not exhibit this behavior when streaming on my desktop, nor, on another, much older Roku (Roku 3?) attached to a FHD Samsung TV or to the same LG TV via Chromecast.
- The Roku does not exhibit this behavior if I watch Netflix or Amazon - only if we stream content from the Tablo.
- The TV does not go into sleep or standby mode regardless of how long it is left switched on or unattended.
- I cannot use a different HDMI port on the TV - it has only one port that supports HDCP 2.2
- I did call Roku technical support. IMHO they were spectacularly unhelpful, suggesting only that I switch HDMI ports or try another electrical outlet. This again, despite the fact that unless the Roku app is involved, the TV never exhibits any behavior of going into sleep mode.
I've broached this with Tablo on their support forums, but they could only suggest that I try a different HDMI cable - which I did. To no avail. They also suggested I contact Roku, since in their words "We've seen Roku HDMI issues in the past (one of their HDMI errors is one of the most viewed threads on our forum)."
I am literally at my wits' end here. I have no idea how to troubleshoot this issue any further.