Overview: Recently while trying to test out the HDMI function on our JVC HD-56G886a, we found that it was in complete dysfunction. The only visible video were flashes when the screen resolution was changed or when the connection was disconnected and reconnected, and a dark green screen that would just stay on when HDMI was connected.

Cause: JVC HDMI is prone to this kind of  failure. The board can simply develop a temporary issue, resolved by resetting, or HDMI may get disabled due to a light sensor on the back of the television which disabled HDMI when light is shined on the back of the T.V. This is a safety feature, televisions should not operate with direct sunlight on the back.

Solution: Do an HDMI reset.

To reset HDMI on the TV, do the following:

Get your original JVC remote

Switch the television input to the tuner (as if you were going to tune into antenna TV).

Make sure that the remote selector is switched to TV.

Press the SLEEP button on the JVC remote until the SLEEP function shows 0 minutes (this should be the default sleep time)

After pressing the SLEEP button, press the Video Status and Display Buttons simultaneously.

A service menu should appear.

Press the number 2 on your remote for “Self Test”. Do not attempt to use any of the other menus.

Power off your TV. If you are using a projection TV, make sure the internal fans finish cooling and stop before the next step.

Unplug the TV for one minute.

Plug back in, power on the TV. This should resolve the issue, however some users report that they have had to repeat these steps once or twice.

Connect your device. HDMI should work.

If this fails, you may need to replace the board.

Resources and verifying sources:

http://www.justanswer.com/tv-repair/5r973-jvc-hd70fh96-hdmi-inputs-don-t-work-saw.html

http://www.justanswer.com/tv-repair/606pl-jvc-hd-55g466-tv-hdmi-needs-reset-power-failure.html

http://www.fixya.com/support/t213989-hdmi_input_failure