Question: Troubleshoot Magnavox DTV digital to analog converter with garbled video output

I retired this box because the video output failed but I'd like to see if
there's component that I could replace to fix it. I inspected the capacitors and
they all look normal.

In the URL below you can see the output from the unit.


I am guessing that the problem was the input signal. I fiddled with the box this evening and couldn't duplicate the image I sent in, but even better, I was able to
get several channels with sound and it all seems to be working just fine. I reassembled the case and chalk the success up to blind luck.

Thanks everyone for your support and help.