Need help on Motorola 6412 DVR..........

I have a Comcast Motorola 6412 DVR. I'm on my 4th one now.
I was able to use HDMI output from box to TV.

I got my box swapped out & now I can't any picture using the HDMI output ?

I can only get a picture using componenet cables. Any ideas on what it could be, or what I could do ?

The DVR I had before this one was able to get picture & sound, using HDMI output.

It's the same model # as the last one , I had.