PACE IPH8010 does not output sound

I have a PACE IPH8010 DVR connected via HDMI to a Sony STR-DN860 media controller which is then connected to a Samsung UN75JU641DFXZA television.  On Thursday, the Pace DVR stopped outputting sound.  I have tried changing the input of the Sony media controller used for the PACE DVR, as well as changing the HDMI cable used to connect the Pace DVR to the Sony media controller and neither solves the issue.  I have also rebooted the Pace DVR, which also did not solve the problem.  Two other Uverse receivers, 1 wired and 1 wireless, in the house are not suffering from the same problem.

Has anyone experienced this and/or does anyone have any recommended troubleshooting steps?