Sony STR-DB940 Operating Instructions Manual page 24

Before You Use Your Receiver
There is no sound no matter which component is
selected.
+ Check that both the receiver and all components
are turned on
W Check that the MASTER VOLUME control is not
set at 0
I, Check that the SPEAKERS selector is not set to
OFF or to a position for front speakers that are not
connected to the receiver (see "a SPEAKERS
selector" on page 30)
+ Check that all speaker cords are connected
correctly
* Press the MUTING button to turn off the indicator
on the button
There's no sound from a specific component.
+ Check that the component is connected correctly to
the audio input jacks for that component
+ Check that the cord(s) used for the connection is
(are) fully inserted into the jacks on both the
receiver and the component
No sound is heard from one of the front
speakers.
* Connect a pair of headphones to the PHONES jack
and set the SPEAKERS selector to OFF to verify
that sound is output from the headphones (see "a
SPEAKERS selector" and "PHONES jack" on page
30)
If only one channel is output from the headphones,
the component may not be connected to the
receiver correctly Check that all the cords are fully
inserted into the jacks on both the receiver and the
component
If both channels are output from the headphones,
the front speaker may not be connected to the
receiver correctly Check the connection of the
front speaker which is not outputting any sound
If you encounter a problem that is not included above, see
"Troubleshooting" on page 56
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