Audio Output Error (7X) - Sony KDS-50A2000 Training Manual

Audio Output Error (7X)

(Reference Figure 5-8) This error is relatively straightforward. The error
occurs when one of the audio outputs is shorted or if a DC voltage level is
present. In either case the problem exists within the audio circuit, which
are located solely on the A1-Board.
The first step in troubleshooting a 7X audio error is to listen for the
presence of audio at initial power ON and before shutdown. This clue will
quickly steer you in the right direction to the defective component.
Is
Audio heard No
before
Shutdown?
Yes
TVP-23
7X Flash
Pattern
(Audio Output )
Is
Audio heard No
before
Shutdown?
Yes
Check
Speakers &
Connections
Do
Replace
Speakers
No Speaker(s)
Measure
1-826-475-11
8 ohms
or Repair Connections
?
Yes
Replace
A1-Board
A-1205-146-A (50")
A-1205-145-A (55")
A-1205-144-A (60")
If no audio is heard before shutdown then the speakers and/or speaker
connections may be defective or damage. The speakers sure measure 8
ohms. Check all connectors and wiring for damage. Replaced and repair
where needed.
If the TV still shuts down (7X), then the problem is with the TV
microprocessor, and consequently, the A1-Board must be replaced.
Is
Audio heard
before
Shutdown?
Yes
Check 6.5V at
CN6901/pins 4-6
*Before Shutdown
Is voltage
6.5V
Present?
Replace
G-Board
A-1186-654-A
If audio is heard before shutdown, then the defect is located on either the
A1-Board or the G-Board. Check for the presences of 6.5V at CN6901/
pin 4 through 6 to determine if the power supply (G-board) has failed.
The 6.5V feeds the D3.3V regulator on the A1-Board. The D3.3V among
other uses is the pull-up voltage supply for the Audio DC-Protect line.
Therefore, a lose of 6.5V will pull that line low and the TV microprocessor
will detect an audio failure.
If the 6.5V is missing replace the G-board because there is a main power
supply failure. If the 6.5V is present replace the A1-board because there
is a D3.3V regulator or TV microprocessor failure. Check all inter-board
5. Protection Circuits
No
Replace
A1-Board
Yes
A-1205-146-A (50")
A-1205-145-A (55")
A-1205-144-A (60")
No
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