KRELL 707, HDMI input and output (including audio and video) does not respond!

Fault description: My KRELL 707, HDMI input and output (including audio and video) does not respond! Whenever HDMI input is used, the machine display shows waiting for audio, and the TV shows no signal input. However, the optical front and coaxial input are normal. I found that some 707 users on the forum also encountered this problem. Is it a common problem? How to solve it? Thank you

Great brand with impressive performance.

If the unit is still under warranty, you should be able to get it serviced by KRELL.

My advice - be careful and use a hair dryer - COOL setting on the HDMI port. Buy a new HDMI cable or use a spare to test It again.

Upon 2nd failure after this, unplug all cables from the unit. Make sure it is powered off and unplugged from power before doing this. Wait for 10 minutes. Then test again.

This should not be happening on such a high-end piece of gear. If it still doesn’t work, then it is definitely a port issue. You cannot repair this yourself and will need to contact KRELL.
Does this happen on all HDMI ports?  Something to check.  Otherwise, you are better off sending it to Krell for repair.
You might try removing the HDMI board and cleaning the contacts with contact cleaning solution.  The HDMI board can be removed  by removing two screws on back.  The top cover has to removed so that you can carefully push the circuit board out. Give this a try before send the unit in for repair.
HDMI boards seem to be a pretty common failure point in many AV processors and receivers.  I don't know about issues with Krell in particular.  You might try posting the AVSForum, there's more focus on home theater in that forum.