I've seen this with some odd HDMI issues. The usual fixes are and to be clear not always a sure thing:
1. Unplug one end of each HDMI cable. Remove power from ALL gear that has HDMI ports. Wait about 10 minutes. Plug it all in, power up and test.
Why this works. Turns out some HDMI chipsets don't really have a good reset so when they get into "HDMI HANDSHAKE ISSUES" this can clear that up.
Also worth noting is that some owners will not accept this fix. Defer to the makers and mention they will be returning gear if they feel this is a product defect.
2. Replace all the HDMI cables with your favorite brand. Here that's the AmazonBasics cables.
So I have Samsung 40MU6100 and sometimes the TV suddenly loses power (goes blank with no video and audio) for about 1-2 seconds and then comes back normal the next second. This happens randomly like it may occur 2-3 times in a minute, or doesn't happen in an hour or so.
I thought the problem is from my Cable STB but when I switch to other HDMI device (PC), the problem also occurs. Strangely when I run TV apps it doesn't happen. Beside STB and PC, I also connect my HTS (Samsung HT-J5100K) through HDMI ARC port.
Please help, thanks!