There's definitely an issue regarding the hdmi video output on the DQ77KB. The first DQ77KB board that I had was experiencing video problems. I ended up with a bad bios flash and had to use the Intel warranty to get a replacement. The replacement board I received was a refurbished board and I had to fork out $25.00 for the shipping.
Anyways, I'm using the refurbished board and have been experiencing the same video problems as the first one I had. I'm connected via the boards hdmi port to my monitors hdmi port. Sometimes I get video and sometimes I don't. When the video doesn't work my monitor says it has no video signal. I'm currently using the latest bios version 049 dated 01/31/13. I've tried most of the other bios versions as well with similar results.
I'm wondering if this could be some sort of power issue for this particular motherboard. I have an external power supply (similar to laptop power brick) that I'm using. I'm wondering whats others have been using and if this could be the issue.
Computer build specs
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Motherboard: DQ77KB Bios 049
CPU: Intel I3-3220T
Monitor: Hanns-G HZ281HPB
Power Supply: 19v/8.4A 160 Watt AC-DC Power Adapterhttp://www.mini-box.com/19v-8-4A-160-Watt-AC-DC-Power-Adapter
If we could, can we start getting people who are having video issues post their computer system specs. I think might turn out to be very helpful to sort this issue out.