Sony KDL-55BX520 Service Manual ▷ View online
KDL-55BX520
20
SECTION 6 - DISASSEMBLY/PART NUMBER INFORMATIONCHASSIS OVERVIEW
DIAGRAMS
COMPOSITE OR
COMPONENT 1
RF
COMPONENT 2
HDMI 1
PC HD15
POWER SUPPLY
SWITCH
UNIT
LED
IR RX
LCD PANEL
A
H
L
R
ANALOG AUDIO OUT
OPTICAL AUDIO OUT
U3
MT5388
A/V DECODER
A/V PROCESS
CPU
TUNER
USB2.0
HDMI 2
LVDS
24V B+
AND CTL
AC IN
INVERTER
U8
CLASS D
AUDIO
AMP
G17
*HDMI 3
*BX421 MODELS
ONLY
IC4305
TEMP
SENSE
FRAME
RATE
CONV
FRC
FIGURE 3-2. OVERALL BLOCK DIAGRAM
BLOCK DIAGRAMS
KDL-55BX520
21
SECTION 6 - DISASSEMBLY/PART NUMBER INFORMATIONCHASSIS OVERVIEW
FRC
Panel
DDR II*2
Inverter
Inverter
FIGURE 3-3. ENGINEERING BLOCK DIAGRAM
KDL-55BX520
22
SECTION 6 - DISASSEMBLY/PART NUMBER INFORMATIONCHASSIS OVERVIEW
MB
PSU
Inverter
KEY PAD
IR
SPEAKER
FIGURE 3-4. CONNECTOR DIAGRAM
CONNECTOR DIAGRAMS
KDL-55BX520 23
OVERVIEW
Most troubleshooting for this chassis focuses on the 3 major
components used:
•
The Main Board (A)
•
Power Supply
•
LCD Panel
This chapter provides practical troubleshooting procedures based
on the various symptoms that will appear when a particular circuit
fails to operate properly. Typical failure symptoms will be discussed
in this chapater with troubleshooting flowcharts for each symptom in
the
Section 5 - Flow Charts and Diagrams on page 32
.
NOTE: Always remember to check the Sony Authorized Servicer
Portal at
www.sony.com/asp
to access the latest technical bulletins
along with triage charts to quickly identify the most like part to
complete the repair based on the symptom.
UPDATING THE SOFTWARE
As mentioned in
Section 2 - Software Requirements
, there are
several issues that may be resloved by updating the software to the
latest version. For a list of possible correctable issues see
Checking
the Software Version on page 15
.
SECTION 4 - TROUBLESHOOTING
VIDEO FAILURES
Problems that develop in the video circuits can appear as subtle or
major distortions, a loss of one or more colors, improper video level,
or a complete loss of video. When troubleshooting LCD display
devices the problem must be isolated to 2 major components: The
Main Board where the video processing is performed or the LCD
Panel. In some cases the TCON may not be available as a separate
component and replacement of the LCD Panel is required to rectify
a TCON problem.
Distortion in the video signal that affects all inputs can be challenging
Distortion in the video signal that affects all inputs can be challenging
at times since any of the above mentioned components can be the
cause. Fortunately, each of these components tends to generate
unique symptoms when a problem occurs. Some distortions may
occur that could be caused by either of these components but a
good understanding of the circuits and further investigation will
isolate the suspected circuit. The following sections will cover the
various scenarios of problems that may occur in the video processing
circuits.
NO VIDEO
A “no video” complaint can be caused by a number of reasons. The
first step is to determine if the condition is present from all input
sources. If any video source is working properly, the TCON (located
within the LCD Panel) can be assumed to be OK. The backlights are
also functioning properly. Although it is unusual for a backlight failure
to cause a complete loss of video (the TV will shut down if a backlight
power or open LED is detected) there have been cases where the
backlights have failed to turn on without the unit shutting down.
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