I have a black display problem too, but I don’t think it’s an HDMI cable issue.
I have a 3710X Roku Express+, software version 9.2.0 build 4804-28. Beginning not later than March 14 when I first noticed the problem, and not earlier than March 10 when all was fine, I get a black screen for all video content on all my channels (Netflix, Amazon Prime, Hulu, Comedy Central, Roku Channel, ...)
Understand, ONLY video doesn’t work. Audio plays fine. Subtitles also play just fine. Static images during menu/channel/program selection display fine, as does video during the 30 seconds or so of Netflix previews. But once any program begins, video goes black.
Given these symptoms, I don’t believe this would be a bad HDMI cable. The cable worked fine for well over a year, during which no one touched it. I have NEVER heard of a cable just going bad from regular use. I’ve also unplugged/reconnected both ends, no change. I have not tried a full reset of the box.
It’s also not some sort of funkiness in the TV, since the satellite TV on HDMI 1 (Roku is on HDMI 2) works fine.
I’m also having black screen picture only issues. Volume works fine, menu to pick out what to watch works. But as soon as I hit play it’s black, even if I hit forward it shows at bottom of screen. I’ve tried many different apps & called internet company. Only thing thing I can do because it’s a Netflix TV is watch that. I have a Roku express.
It seems almost everytime I turn on my TV I no longer see the Roku home screen but the no signal message. I am able to get the Roku home screen to pop up after I unplug the power cord to my RokuStreamingStick+ > I have a new Sony Bravia XBR-49x800 series TV and has worked well since I bought it in December.
Since multiple people are reporting the same problem, and my and others' troubleshooting shows it is NOT something with the HDMI cable, but that the Roku box periodically needs a hard (power-up) reset, you should update your recommendation to include that, rather than always point to the HDMI cable.