Audio System Troubleshooting; Normal Operation; Missing Audio; Distorted Audio - Sony KLV-40ZX1M Training Manual

Audio System Troubleshooting

Reference Figure 2-7

Normal Operation

There is only one audio input on this model, and that is over the HDMI.
Furthermore, there is only one audio output on this model, and that is the
main speaker outputs (Left, Right, and Sub-Woofer).
The HDMI connects at the HSL-Board. The HSL-Board contains the
HDMI interface circuit and EDID EEPROM. After passing through the
HSL-Board the HDMI digital audio signal is applied to the TRIDENT IC on
the B-Board. The HDMI audio signal is converted to an I2S and output to
the Audio DSP IC.
The Audio DSP outputs the individual Left, Right. and Sub-Woofer audio
signals to the appropriate amplifier IC. The Left and Right audio signals
are applied to IC2004 and the Sub-Woofer audio signal goes to IC2005.
The Reg 12V from the GS1-Board is the power supply for both main and
sub-woofer amplifier ICs.
The speaker system (Left, Right, and Sub-Woofer) are located in the
TV-STAND. Two cables come off the B-Board and are combined into a
single connector at the center back of the TV chassis near the AC power
connection. The speaker connections are made when the TV chassis is
placed on the TV-STAND. The left and right speakers measure 8 ohms
each and the sub-woofer measures 4 ohms.
A "Speaker Detect" pin is also included on this connector which notifies
the BE-Microprocessor that the TV-STAND (Speakers) are successfully
connected to the TV chassis. This line should be low (0V) when the TV-
STAND is securely connected. The TV-STAND applies a ground to the
"Speaker Detect" line when connected.

Missing Audio

In this case, the most likely defect is the B-Board. Before you replace
the B-Board perform the following test procedures to confirm the actual
CTV-54
defective component.
1) Replace external device with known good device
a) Audio OK (repair external device or connections)
b) No Audio. Go to Step 2
2) Check "Speaker Detect" at CN2000/pin 6
a) 3V level - Check TV-STAND connection or replace
b) 0V level. Go to Step 3
3) Check for 12V at CN2502/pin 3 on B-Board
a) No 12V. Repair CN2505 or CN6156 connection
b) 12V Present. Go to Step 4
4) Replace B-Board
a) Problem Solved
b) Still No Audio - Replace HSL-Board

Distorted Audio

The external device and its associated cable connected to the input should
be checked first.
Substitute a known good device and cable on the HDMI 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.
Because there is no other audio outputs on this model such as ,a
headphone or var/fix, the only way to determine the component causing
the audio distortion is to board swap. The suggested sequence for the
most effective and efficient board swapping is as follows.
1) B-Board (Audio Processing)
2) HSL-Board (HDMI Interface)
3) TV-STAND (Speakers)
Troubleshooting
23