You don't say which component of the HDMI is not working: video, audio or both?

Are we so sure there's a hardware failure that we need to perform surgery first?

http://www.retrevo.com/support/Harman-Kardon-AVR-347-Receivers-manual/id/2782bh929/t/2/

Do BOTH HDMI ports fail? Have you verified the digital assignments?

On page 11 is a note:

NOTES:

• Due to copy-protection restrictions, there is no output at the

Component Video Monitor Outputs for copy-protected

sources.

• High-resolution 1080i and 1080p video signals are not

available at the HDMI Output, but 1080i signals are passed

through, as is, to the Component Video Outputs. If your

source output is analog high-resolution video, either use the

AVR's Component Video Outputs, lower the output resolution

of your source device, or connect your source's component
video outputs directly to your video display.

Hi,

It looks like the hdmi controller has gone bad. The best thing to do is have it serviced. This website will tell you where the closest service center is.

http://www.harmankardon.com/EN-US/Products/Pages/ProductDetails.aspx?PID=AVR%20254&accT=1&tsT=0&ovT=1
I wish i could have a better solution.

Let me know,if needed further assistance.

Hope i helped you.

Thanks for using ' Fixya ' and have a nice day!!