The 3rd-gen Fire TV Cube is the first Fire TV to come with an option that Fire TV users have literally been asking for since the original Fire TV debuted in 2014. In its display settings is finally an option to make the Fire TV Cube output no video signal when it goes to sleep, as opposed to outputting an all-black video feed, which is what all prior Fire TVs do. The “No Signal” option, which is on by default, for the new “Sleep Mode Behavior” menu will finally allow your TV to automatically turn off when the Fire TV goes to sleep.
All Fire TVs prior to the new Fire TV Cube 3 display a black screen when asleep with no other option. Since the black sleep screen is as much a valid video signal as actually watching something, all TVs will treat it as if someone is using the TV and stay powered on indefinitely. I’m sure a lot of you can relate to walking into a room and seeing a faint glow from your TV’s black screen and realizing that you or someone in your house has left the TV on for hours because of the Fire TV’s black sleep screen.
If you’re a psychopath and like the black screen sleep mode, you can still turn it on in the new Cube’s display settings. In all seriousness, you may find that, while the behavior of a black screen during sleep isn’t ideal, it may be necessary for some TVs that have trouble detecting HDMI signals correctly when the Fire TV wakes up. HDCP, the copy protection used by most modern TVs and streaming devices, can be a bit finicky sometimes when devices wake up, resulting in no signal at all or error messages. If you run into that with the new Cube, you may want to turn the black screen sleep behavior back on.
The Fire TV Cube 3 is running a slightly newer version of Fire OS, v126.96.36.199, than all other Fire OS 7 devices, which are currently on v188.8.131.52. Hopefully, that means this new sleep behavior option will be coming to other Fire TV models in the future when they sync up with the Fire TV Cube 3’s newer OS version.