Sony KDL-32BX311 Service Manual ▷ View online
KDL-32BX311
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SECTION 4 - TROUBLESHOOTING
POWER SUPPLY TROUBLESHOOTING
Failures in the power supply circuits that prevent the TV from turning
on are caused by one of the following scenarios:
•
Complete failure of the standby and main power supplies.
•
Failure of the main supply including the main switching regulator,
PFC circuit, main relay and other components required to turn
the circuits on.
•
The power supply is not receiving a turn-on command from the
CPU.
COMPLETELY DEAD SET
A complete power supply failure is generally the result of severe
transients in the AC line such as those incurred during an electrical
storm. This model line utilizes a red standby LED located on the
lower left front bezel that is lit whenever the TV is receiving AC
power and is turned off. If it is not lit, and AC power to the television
is confirmed, replacement of the power supply board should rectify
the problem.
TV WON’T POWER ON
This situation assumes that the red standby LED is lit when AC power
is applied to the TV. A lit standby LED indicates that the standby
power supply is operational, and the CPU on the main board is at
least partly operational. In this case it is likely that the main power
supply is either not being turned on or it has failed. Use the power-on
button on the right side of the TV to attempt a turn-on and eliminate
a defective remote control system.
“Figure 5-3. Power Supply
Flowchart” on page 28
will assist in isolating the power problem.
BACKLIGHT ISSUES
Under normal circumstances, any failures in the backlighting system
will cause the unit to shut down. If any section of the inverter circuits
fails to operate properly, the unit will shut down and blink the standby
LED in groups of 6.
If one or more of the fluorescent backlights fails to light, the over-
If one or more of the fluorescent backlights fails to light, the over-
voltage protection circuit of the inverter is activated. The inverter
shuts down and the same 6-blink protect event occurs.
The recommended approach for a 6-blink shutdown is to determine
The recommended approach for a 6-blink shutdown is to determine
if the backlights are turning on before the shutdown. The easiest
way to determine this is to watch for the Sony logo to appear on the
screen. The television will make 2 or 3 attempts to achieve proper
lighting of the lamps. If the Sony logo appears, the backlights are
turning on and the problem is likely due to one of the lamps not
lighting. If the lamps never turn on and no Sony logo appears on the
screen, the inverter is the likely suspect.
NO BACKLIGHT, NO SHUTDOWN
It is possible for a symptom of no backlighting to occur that does not
cause the television to go into protective shutdown. Dynamic dimming
control of the backlights is performed by monitoring information from
the TCON circuits. This is in the form of data and determines the
brightness level of the backlights based on video content.
If the TCON fails to process the RGB video data, or if the dimmer
If the TCON fails to process the RGB video data, or if the dimmer
data line fails, the backlights will not turn on. Audio will be present
if the selected input has it available. The television will remain on
indefinitely with the green Power LED lit. In this scenario, the LCD
panel must be replaced.
KDL-32BX311
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SECTION 4 - TROUBLESHOOTING
PROTECTION SHUTDOWN
Self Diagnosis
Supported model
Critical voltages and circuit operations are monitored by the CPU
on the main board. If a fault is detected the Self-Diagnostic function
in the TV will force the TV to shut down by the CPU. The monitored
circuit in which the fault occurred will cause the CPU to flash the
Stand-By LED in groups of repeating sequences. The number of
blinks in these groups identifies which voltage or circuit caused the
protection event.
Not all of the available protect codes are used in every model. For
Not all of the available protect codes are used in every model. For
example, models that are LED backlit do not use the 4-blink balancer
error as this circuit is found in models that are backlit with fluorescent
lamps. The following list contains the protect circuits and diagnostics
codes used in the models listed in this manual.
“Figure 5-4. Protection
Shutdown Flowchart” on page 29
provides guidance in locating
the possible component causing the shutdown.
STANDBY LED FLASH COUNT
FIGURE 4-1. LED DISPLAY
2 times
5 times
LED ON 0.3 sec.
LED OFF 0.3 sec.
LED OFF 0.3 sec.
LED OFF
3 sec.
FIGURE 4-2. BLINK COUNT
KDL-32BX311
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SECTION 4 - TROUBLESHOOTING
2X Blink - Main Power Error
A loss of REG12V from the power supply triggers this protect
A loss of REG12V from the power supply triggers this protect
event. This symptom is usually remedied by replacing the power
supply board. If the error continues after the power supply board
is replaced, suspect excessive loading which is causing the power
supply to shut down. This is usually caused by a failure of the inverter
circuits. Unplug the inverter and turn the TV back on. If a 6X error is
displayed, the inverter (or LCD panel) must be replaced.
3X Blink- DC Regulator/Audio Error
The REG 5V and D3.3V source originating on the main board is
3X Blink- DC Regulator/Audio Error
The REG 5V and D3.3V source originating on the main board is
monitored for low-voltage conditions by the CPU. A failure causing a
3X shutdown would require replacing the main board.
5X Blink - TCON Error
A communications error with the timing control circuits (TCON) has
5X Blink - TCON Error
A communications error with the timing control circuits (TCON) has
occurred. If the TCON is available for replacement, replace the
TCON. If the TCON is not available, the LCD panel must be replaced
since the TCON circuit is part of the LCD panel assembly. In rare
cases a loose or defective LVDS cable could also be the cause.
6X Blink - Backlight System Failure
If the inverter circuits fails to generate high voltage or one or more
If the inverter circuits fails to generate high voltage or one or more
of the backlight lamps fails to light, the television will shut down
and display this diagnostics error. Observing for the presence of
backlighting is crucial in determining which component is likely at
fault.
If the backlights turn on before the 6X shutdown occurs, it is safe
If the backlights turn on before the 6X shutdown occurs, it is safe
to assume that the inverter circuits are functioning and one of the
lamps failed to ignite. Replacing the LCD panel is necessary. If the
backlights never turn on before the 6X shutdown, the inverter has
failed. If the inverter is available for replacement, replace the inverter.
If the inverter is not available, replace the LCD Panel.
7X Blink - Temperature Failure
A digital thermometer IC located on the main board provides a
7X Blink - Temperature Failure
A digital thermometer IC located on the main board provides a
temperature reading of the chassis and LCD panel. If the temperature
exceeds a pre-determined point the TV will shut down. If this problem
occurs immediately at turn-on, the temperature sensing IC has failed
and replacing the main board is required. If this occurs after the TV
has been running for a while, check for ventilation issues that could
cause the TV to run hotter than normal.
KDL-32BX311
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SECTION 4 - TROUBLESHOOTING
DIAGNOSTIC CODE DESCRIPTIONS
The Diagnotic Table provides an overview of the number of times the Standby LED blinks and the possible location.
Diagnostic Item
Diagnostic Item
Description
Number of times
Standby LED blinks
Possible Location
MAIN_POWER
Main Power Over Voltage Protection
2
G13 Board
BALANCER
Panel Balancer Error
4
NOT USED
TCON ERR
TCON Error
5
LCD Panel
BACKLITE
Backlight Error
6
LCD Panel
TEMP_ERR
Temperature Error
7
A Board
DC_ALERT AUD_PORT
DC Alert
Audio Error Detection
A Board
3
FIGURE 4-3. DIAGNOSTIC TABLE
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