Onkyo TX-NR 838 Manual page 140

Troubleshooting
Audio
There is no sound, or it is very quiet
Make sure that the proper input source is selected.
Make sure that connecting plugs are pushed in all the way.
Make sure that the inputs and outputs of all components are connected
properly.
Make sure that the polarity of the speaker cables is correct, and that no
bare wires are in contact with the metal part of speaker terminals.
Make sure that the input source is properly selected.
Make sure that the speaker cables are not shorting.
Check the volume. The volume level is adjustable between Min, 1 to 79,
Max (100) It is normal that the unit volume level is set up to 40 or around.
If the MUTING indicator on the display flashes, press MUTING on the
remote controller to unmute the unit.
While headphones are connected to the PHONES jack, no sound is
output from the speakers.
If there is no sound from a BD/DVD player connected to an HDMI IN,
check the BD/DVD player's output settings, and be sure to select a
supported audio format.
Check the digital audio output setting on the connected component. On
some game consoles, such as those that support DVD, the default setting
is off.
With some DVD-Video discs, you need to select an audio output format
from a menu.
If your turntable uses an MC cartridge, you must connect an MC head
amp, or an MC transformer.
Make sure that none of the connecting cables are bent, twisted, or
damaged.
Not all listening modes use all speakers.
Specify the speaker distances and adjust the individual speaker levels.
Make sure that the speaker setup microphone is not still connected.
If the input signal format is set to "PCM" or "DTS", set it to "Off".
Only the front speakers produce sound
When the Stereo or Mono listening mode is selected, only the front
speakers and subwoofer produce sound.
Make sure the speakers are configured correctly.
Only the center speaker produces sound
If you use the Dolby Pro Logic II listening mode with a mono source, such