Audio Troubleshooting; Missing Or Distorted Main Speaker Audio - All Inputs; Missing Or Distorted Main Speaker Audio - Individual Inputs - Sony KDL-40SL140 Training Manual

into zones over the entire screen. Therefore, a gamma distortion
can show up as a color brightness irregularity in specifi c zones
or specifi c color areas in the picture, as well as an irregularity in
overall picture brightness.

Audio Troubleshooting

Reference Audio System Block Diagram
The fi rst step when a "Missing or Distorted Audio" defect occurs is to
determine if audio is missing or distorted on all audio input sources or
only on one or a select number of audio input sources.
Input Status:
• Missing or Distorted Audio on All Inputs
• Missing or Distorted Audio on Individual Inputs

Missing or Distorted Main Speaker Audio - All Inputs

In this case, the most likely defective is the BM5-Board. Before you
replace the BM5-Board perform the following test procedures to confi rm
the actual defective component.
1) Check for audio at the FIX, HEADPHONE, or DIGITAL Audio
Outputs
a) No or Distorted Audio (Replace BM5-Board)
b) Audio Present & Undistorted. Go to Step 2
2) Check for AU15V at CN4001/pin 1 on BM5-Board
a) No AU15V replace IP5Z Board
b) AU15V Present replace BM5-Board

Missing or Distorted Main Speaker Audio - Individual Inputs

If only one or a select number of input sources are experiencing a problem,
then the individual inputs must be checked separately. The external
devices and their associated cables connected to the faulty input should
be checked fi rst.
CTV-51
Substitute a known good device and cable on the suspected faulty input.
Connect the device and cable at separate times to determine if the device
or cable is causing the problem. Replace the device or cabling if found to
be defective. However, if the external device and cables are okay, then
the next step is to replace the common board or module associated with
that particular input source.
For example, consider the symptom of all or only one or two of the
Composite 1, 3 or NTSC inputs are faulty. Logically the only device that
could cause this symptom is the switcher IC2014 on the BM5-Board. The
most likely problem is one or more of the switcher inputs are defective. In
this case, replace the BM5-Board.
Another example would be missing or distorted audio on one or both
HDMI input only. The only component that would affect only the HDMI
audio inputs is the HDMI receiver IC5801 on the BM5-Board. Therefore,
replacing the BM5-Board should fi x this problem.
Troubleshooting
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