Sony KDL-32BX320 / KDL-32BX321 / KDL-32BX420 / KDL-32BX421 / KDL-40BX420 / KDL-40BX421 / KDL-46BX420 / KDL-46BX421 Service Manual ▷ View online
KDL-32BX320/32BX321/32BX420/32BX421/40BX420/40BX421/46BX420/46BX421 24
SECTION 4 - TROUBLESHOOTING
TCON: Since the TCON allocates the RGB video information based
on specific timing information, the distortions tend to be fixed and
usually appears as symmetrical patterns that occupy most (or a
significant portion) of the display. The TCON circuits in this chassis
are integrated within the LCD panel which requires replacement of
the entire panel to remedy a TCON failure. Some examples of TCON
errors:
•
No video
•
Thin vertical lines spanning most or all of the display
•
More that one column of wide vertical columns which may
appear black or any color, or may contain distorted video.
•
Multi-colored vertical line patterns with a repetitive pattern
Service Tip: Whenever vertical lines of distortion appear, select an
inactive input or disconnect the antenna in the tuner mode. The idea
is to not have a high-definition signal as the source. This allows the
picture zoom functions to operate.
Change the zoom mode from the remote commander. If the lines
Change the zoom mode from the remote commander. If the lines
follow the normal and zoom modes the problem resides on the main
board. If the lines remain fixed throughout the various zoom modes
the TCON is at fault.
LCD Panel: Distortions originating from the LCD panel tend to be
LCD Panel: Distortions originating from the LCD panel tend to be
localized with the exception of horizontal line issues. A failure of a
gate driver can cause a horizontal distortion with all video content
below that point appearing distorted. Depending on which gate driver
has failed, the distortion may only cover a small area of the bottom of
the screen if the driver failed near the bottom of the panel, or a large
area of the screen if the driver failed near the top of the panel. With
the exception of visible physical damage, the following are some
examples of LCD panel related distortions:
•
Any single, thin vertical line (regardless of color)
•
Any thin vertical lines isolated to a specific area of the screen
•
A singe vertical column of lines of any color or containing
distorted video
•
Any fixed horizontal lines
•
Blotches of black or improperly colored areas
•
Ghosting of images in which the entire image is repeated one
or more times
A thorough understanding of how the video is processed throughout
the chain of circuits all the way to the panel is important. A past
article written for the Sony Newsletter described, in detail, how this
process works.
Figure 5-2. Video Distortion Flowchart on page 32
will assist in isolating
which component is causing the distortion.
AUDIO TROUBLESHOOTING
Since all audio signals are input, processed and amplified by the
main board, any issue involving the loss of audio or audio distortions
which are present at all inputs would dictate that the issue can be
resolved by replacing the main board. It is possible that a software
update might also resolve the issue, but it is very unusual for a
software update to affect all sources. Once again, always check
the Sony Authorized Servicer Portal at
www.sony.com/asp
for any
known and/or listed issues that are software related.
Audio problems that are input specific (especially the HDMI and
Audio problems that are input specific (especially the HDMI and
digital sources such as the USB input and tuner) are more likely to
point to the need for a software update and this is especially true if
the problem is intermittent.
KDL-32BX320/32BX321/32BX420/32BX421/40BX420/40BX421/46BX420/46BX421 25
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 33
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-32BX320/32BX321/32BX420/32BX421/40BX420/40BX421/46BX420/46BX421 26
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.
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 34
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-32BX320/32BX321/32BX420/32BX421/40BX420/40BX421/46BX420/46BX421 27
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.
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