Had a movie recording on tuner 2 and was watching a recorded program on a 622 using TV 1 last night when I pushed something on the remote without looking where I was pushing. I intended to skip forward during a commercial but obviously missed my target. The program continued to play but suddenly there was no sound. I stopped the recorded program and found there was no sound on live programming from tuner 1 either.
My audio goes through an A/V receiver via optical digital so I ran some tests on the A/V receiver. It was working with other inputs. Then turned on TV 2 for the 622 and found it had no sound either. That told me it was a problem with the receiver. Wondering if it might be a DISH transmission problem, I fired up my other 622 to check. It had sound so the problem was isolated to the single 622. As a last check I switched that receiver to tuner 2, which was still recording. That tuner had sound. Before calling tech support I decided to do what I knew they would tell me to try first. I checked all receiver audio settings, which were okay, and then did a power button reboot. It worked. In five minutes I had sound again on all tuners.
Still don't know what I did to trigger this problem. It's one I've never seen before.