A few users of the recently-released NBC Nightly News app for the Apple iPad have written to say that sometimes there is no sound accompanying a video when played in the app. The Device Development team at MSNBC investigated and has found the cause.
The iPad has a switch on the side of the device, just above the volume control. This switch normally controls sound muting for alerts and notifications, according to a technical article published by Apple, Inc., maker of the iPad.
If the switch is in the down position (see accompanying photo), an orange dot appears and audio is "muted." In addition to muting alerts and notifications this switch affects the sound for some applications, including the NBC Nightly News app for iPad.
Simply move the switch to the up position to enjoy the audio portion of the video story playing in the app.