Audio Symptom Troubleshooting; Normal Operation; Failure Symptoms; Missing Or Distorted Main Speaker Audio - All Inputs - Sony KDL-55EX500 Troubleshooting Manual

Audio Symptom Troubleshooting

Reference Figure 2-9

Normal Operation

The HDMI digital audio signal is first applied to the HDMI Receiver/Switch
IC6601 and then to the MT5388 on the A-Board.
The RF input is first applied to the Tuner and then to the IC400. The Tuner
outputs the ATSC and NTSC signals as an IF signal to IC400.
All other audio inputs are applied directly to IC400. The MT5388 IC400.
outputs the audio signal as a SPDIF signal for the Optical output. The
FIXED analog audio output passes through an amplifier IC8301 and then
is applied to CN8301.
The main speaker audio comes from IC400 and passes through amplifier
IC8151 and then to CN8151 and CN8152 speaker connections..
The AU12V from the G5E, or G8S-Board is the power supply for the audio
output amplifier IC8151.
IMPORTANT:
• Confirm the TV has the most recent Software Version
installed. Go to the User Menu for the present TV software
revision and the ASC web site for the most recent software
version.

Failure Symptoms

The first 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
CTV-65

Missing or Distorted Main Speaker Audio - All Inputs

In this case, the most likely defective is the A-Board. Before you replace
the A-Board perform the following test procedures to confirm the actual
defective component.
1) Check for audio at the Analog FIX or DIGITAL Audio Outputs
a) No or Distorted Audio (Replace A-Board)
b) Audio Present & Undistorted. Go to Step 2
2) Check for AU12V at CN201/pin 1 on A-Board
a) No AU12V - Check connections between the Power Supply
board and the A-Board
b) AU12V Present replace A-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 first.
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 HDMI inputs are faulty. Logically
the only device that could cause this symptom is the HDMI switcher
IC6601 on the A-Board. In this case, replace the A-Board.
AZ1K Chassis Models Overview
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