SONY KDL-40SL140 - KDL-46SL140 LCD TV WORKING AND LED BLINKING TROUBLE SHOOTING
SONY KDL-40SL140 - KDL-46SL140
LCD TV
WORKING AND LED BLINKING TROUBLE SHOOTING
PCB
Functional Descriptions
BM5-Board
The circuits located on the BM-Board perform all Video and Audio processing functions. It also contains all the microprocessor control circuits. The following circuits are included on this board.
# TV Microprocessor
# ATSC/NTSC Tuner
# Xillion Processor
- A/V Processing
- HDMI Processing
- Scan Converter
# Composite Input Terminals
# Component Input Terminals
# HDMI Input Terminals
# PC-IN Input Terminal
# RF/Cable Input Terminal
# Voltage Regulator Circuits
IP5Z-Board (Power Supply & Inverter Board)
The IP5Z-Board includes the typical TV power supply circuits listed in the following bullets. In addition this board includes the Backlight Inverter
circuits.
# Standby Power Supply
# 3.3V
# Main Power Supply
# AU15V
# 12V
Power Factor Control (PFC)
# Inrush Relay
# Main Fuse (F1)
The Backlight Inverter (or power supply) is located on the IP5Z-Board. The Backlight Inverter section develops two 1.1KV high voltage outputs (180 degrees out-of-phase) used to drive the Backlight Balancer Board and subsequently the Backlight lamps.
Backlight Balancer Board
The Backlight Balancer board takes the 1.1KV (HV1 & HV2) from the IP5Z-Board (Inverter section) and disperses the high voltage inputs equally to each lamp ensuring even luminance across the entire LCD panel. The majority of the components on the Balancer board are passive transformers used for the HV balancing function. In addition, there are circuits for the Inverter Feedback signal and LD (Lamp Detection) protection signal development.
HM1-Board
# Channel Up/Down Button
# Volume Up/Down Button
# TV/Video Button
# Menu Button
# Power Button
HM5-Board
# Power LED
# Timer/PIC OFF LED
# IR Sensor
# Illumination Senso
# Inrush Relay
# Main Fuse (F1)
The Backlight Inverter (or power supply) is located on the IP5Z-Board. The Backlight Inverter section develops two 1.1KV high voltage outputs (180 degrees out-of-phase) used to drive the Backlight Balancer Board and subsequently the Backlight lamps.
Backlight Balancer Board
The Backlight Balancer board takes the 1.1KV (HV1 & HV2) from the IP5Z-Board (Inverter section) and disperses the high voltage inputs equally to each lamp ensuring even luminance across the entire LCD panel. The majority of the components on the Balancer board are passive transformers used for the HV balancing function. In addition, there are circuits for the Inverter Feedback signal and LD (Lamp Detection) protection signal development.
HM1-Board
# Channel Up/Down Button
# Volume Up/Down Button
# TV/Video Button
# Menu Button
# Power Button
HM5-Board
# Power LED
# Timer/PIC OFF LED
# IR Sensor
# Illumination Senso
LCD Panel Assembly
The LCD Panel Assembly includes the LCD Panel, TCON, and Backlight Lamps.
The LCD Panel contains the actual liquid crystals, color filters, and polarizers. The liquid crystals are manipulated by the applied voltage to pass a specific amount of light - from the backlight- depending on the level of voltage applied. The panel resolution on all the MA2F chassis models is 1920 X 1080 lines. These are considered 1080p High-Definition models. The TCON performs all the control, timing, charge, and discharge functions driving the operation of the LCD Panel. The Backlight Lamps generate the white light that passes through the liquid crystals in the LCD Panel.
The LCD Panel Assembly includes the LCD Panel, TCON, and Backlight Lamps.
The LCD Panel contains the actual liquid crystals, color filters, and polarizers. The liquid crystals are manipulated by the applied voltage to pass a specific amount of light - from the backlight- depending on the level of voltage applied. The panel resolution on all the MA2F chassis models is 1920 X 1080 lines. These are considered 1080p High-Definition models. The TCON performs all the control, timing, charge, and discharge functions driving the operation of the LCD Panel. The Backlight Lamps generate the white light that passes through the liquid crystals in the LCD Panel.
TROUBLESHOOTING
SYMPTOMS AND SOLUTIONS
Reference the appropriate Block Diagrams in Section 2 of this manual and
the Test Point Diagrams in this section as you read through the following
symptom & solution procedures.
TV will not Turn ON (Dead Set)
In a “Dead Set” condition, no relay click will be heard and there will be no green “Power LED” illumination when a power ON command is received from the Power button on the top panel or remote controller.
One of the following failures has occurred.
# Loss of AC Power to the TV
# Defective Standby 3.3V Power Supply
# Defective Main Microprocessor (IC3011)
Perform the following checks in the sequence of steps shown to efficiently and effectively determine what is causing the “Dead Set” condition.
All connectors are on the IP5Z-Board.
“Dead Set” Troubleshooting Procedure:
1) Check for the presence of 110V at CN6000
a) No 110V. Check AC output and TV power cord.
b) 110V Present. Go to Step 2
2) Check for the presence of Standby 3.3V at CN6150/pin 3
a) No Standby 3.3V. replace IP5Z Board
b) Standby 3.3V Present replace BM5-Board
Reference the appropriate Block Diagrams in Section 2 of this manual and
the Test Point Diagrams in this section as you read through the following
symptom & solution procedures.
TV will not Turn ON (Dead Set)
In a “Dead Set” condition, no relay click will be heard and there will be no green “Power LED” illumination when a power ON command is received from the Power button on the top panel or remote controller.
One of the following failures has occurred.
# Loss of AC Power to the TV
# Defective Standby 3.3V Power Supply
# Defective Main Microprocessor (IC3011)
Perform the following checks in the sequence of steps shown to efficiently and effectively determine what is causing the “Dead Set” condition.
All connectors are on the IP5Z-Board.
“Dead Set” Troubleshooting Procedure:
1) Check for the presence of 110V at CN6000
a) No 110V. Check AC output and TV power cord.
b) 110V Present. Go to Step 2
2) Check for the presence of Standby 3.3V at CN6150/pin 3
a) No Standby 3.3V. replace IP5Z Board
b) Standby 3.3V Present replace BM5-Board
TV Shuts Down and Indicates a
Protection Mode
2X Blink Pattern (Power Supply Failure)
The 2X Blink Pattern usually indicates a loss of the 12V secondary output on the main power supply IC6100. This protection mode basically indicates
a general main power supply failure, which can be caused by one of the following failures
# Defective Main Power Supply (IC6100)
# Loss of 12V
# Loss of POWER_ON signal (Main Microprocessor)
You can determine if one of the previously listed conditions exists by measuring the 12V and listening for the relay click before the TV shuts OFF. If the 12V is not present before shutdown then the IP5Z power supply board is possibly defective. Perform the following checks to determine the defective component.
2X Troubleshooting Procedure:
1) Listen for Relay Click.
a) Relay Click Heard. Go to Step 2
b) No Relay Click Heard. Go to Step 3
2) Check the condition of the 12V at CN6150/pin 11
a) No 12V replace IP5Z-Board
b) *Normal 12V Level replace BM5-Board
*Normal voltage Level - the voltage approaches 12V but does not exceed before shut down.
3) Check for the presence of the POWER_ON voltage at CN6150/pin 1 after pressing the TV ON/OFF button.
a) No 3.3V POWER_ON voltage replace BM5-Board
2X Blink Pattern (Power Supply Failure)
The 2X Blink Pattern usually indicates a loss of the 12V secondary output on the main power supply IC6100. This protection mode basically indicates
a general main power supply failure, which can be caused by one of the following failures
# Defective Main Power Supply (IC6100)
# Loss of 12V
# Loss of POWER_ON signal (Main Microprocessor)
You can determine if one of the previously listed conditions exists by measuring the 12V and listening for the relay click before the TV shuts OFF. If the 12V is not present before shutdown then the IP5Z power supply board is possibly defective. Perform the following checks to determine the defective component.
2X Troubleshooting Procedure:
1) Listen for Relay Click.
a) Relay Click Heard. Go to Step 2
b) No Relay Click Heard. Go to Step 3
2) Check the condition of the 12V at CN6150/pin 11
a) No 12V replace IP5Z-Board
b) *Normal 12V Level replace BM5-Board
*Normal voltage Level - the voltage approaches 12V but does not exceed before shut down.
3) Check for the presence of the POWER_ON voltage at CN6150/pin 1 after pressing the TV ON/OFF button.
a) No 3.3V POWER_ON voltage replace BM5-Board
b) 3.3V POWER_ON present replace IP5Z Board
3X Blink Pattern (D1.8V or D2.5V Failure)
Replace the BM5-Board for this blink pattern. The 3X blink pattern indicates a failure of the D2.5V regulator IC7004, D1.8V regulator IC7005, or an open F7002 or F7001 on the BM5-Board. Although the 12V secondary from the main power supply drives the regulator, a loss of the 12V will cause a 2X blink pattern not a 3X.
4X Blink Pattern (D3.3V Failure)
Replace the BM5-Board for this blink pattern. A 4X blink pattern indicates a failure of the D3.3V regulator IC7004 or an open F7002 on the BM5-Board. Although the 12V secondary from the main power supply drives the regulator, a loss of the 12V will cause a 2X blink pattern not a 4X.
5X Blink Pattern (Panel V Failure)
Replace the BM5-Board for this blink pattern. A 5X blink pattern indicates a failure of the Panel V (12V) regulator Q4018 or an open F4001 on the BM5-Board. Although the 12V secondary from the main power supply drives the regulator, a loss of the 12V will cause a 2X blink pattern not a 5X.
6X Blink Pattern (Backlight Failure)
The 6X blink pattern indicates a Lamp, Inverter Board, or Balancer Board failure. Perform the following checks in the sequence of steps shown to efficiently and effectively determine which component has failed. Confirm CN4003 is securely seated on the BM5 Board and CN6154 is securely seated on the IP5Z-Board before proceeding with troubleshooting steps. A poor connection of the “Inverter Error” line on CN4003 or CN6154 will cause a 6X blink protection mode
3X Blink Pattern (D1.8V or D2.5V Failure)
Replace the BM5-Board for this blink pattern. The 3X blink pattern indicates a failure of the D2.5V regulator IC7004, D1.8V regulator IC7005, or an open F7002 or F7001 on the BM5-Board. Although the 12V secondary from the main power supply drives the regulator, a loss of the 12V will cause a 2X blink pattern not a 3X.
4X Blink Pattern (D3.3V Failure)
Replace the BM5-Board for this blink pattern. A 4X blink pattern indicates a failure of the D3.3V regulator IC7004 or an open F7002 on the BM5-Board. Although the 12V secondary from the main power supply drives the regulator, a loss of the 12V will cause a 2X blink pattern not a 4X.
5X Blink Pattern (Panel V Failure)
Replace the BM5-Board for this blink pattern. A 5X blink pattern indicates a failure of the Panel V (12V) regulator Q4018 or an open F4001 on the BM5-Board. Although the 12V secondary from the main power supply drives the regulator, a loss of the 12V will cause a 2X blink pattern not a 5X.
6X Blink Pattern (Backlight Failure)
The 6X blink pattern indicates a Lamp, Inverter Board, or Balancer Board failure. Perform the following checks in the sequence of steps shown to efficiently and effectively determine which component has failed. Confirm CN4003 is securely seated on the BM5 Board and CN6154 is securely seated on the IP5Z-Board before proceeding with troubleshooting steps. A poor connection of the “Inverter Error” line on CN4003 or CN6154 will cause a 6X blink protection mode
6X Troubleshooting Procedure:
1) Check for Backlight (bright raster) before TV Shut Down. The backlight illumination can also be viewed through holes on the rear of the LCD panel with the TV rear cover removed.
a) No Backlight before Shut OFF. Go to Step 2
b) Backlight ON before Shut OFF. Go to Step 5
2) Check for High Voltage (HV) at CN6700 on IP5Z-Board
a) No HV replace the IP5Z-Board
b) HV Present. Go to Step 3
3) Check for Backlight_ON voltage CN6154/pin 2 on IP5ZBoard
a) No 3.2V replace the BM5-Board
b) 3.2V Present. Go to Step 4
4) Check for LD voltage CN6701/pin 26 on IP5Z-Board
a) No 11V replace the Balancer Board
b) 11V Present replace the IP5Z-Board
5) Check Balancer Board Feedback (FB) voltage CN6701/pin 2
NOTE: Use a DMM or Oscilloscope to measure the ACrms voltage level or wavform level.
a) No FB replace the Balancer Board
b) FB Present. Go to Step 6
6) Check the condition of the individual HV Balancer Board Outputs.
a) Excessive High Level at One or More HV outputs replace LCD Panel Assembly.
b) Excessive Low Level at One or More HV outputs. replace Balancer Board.
c) All HV Output Levels within Spec. Replace BM-Board
1) Check for Backlight (bright raster) before TV Shut Down. The backlight illumination can also be viewed through holes on the rear of the LCD panel with the TV rear cover removed.
a) No Backlight before Shut OFF. Go to Step 2
b) Backlight ON before Shut OFF. Go to Step 5
2) Check for High Voltage (HV) at CN6700 on IP5Z-Board
a) No HV replace the IP5Z-Board
b) HV Present. Go to Step 3
3) Check for Backlight_ON voltage CN6154/pin 2 on IP5ZBoard
a) No 3.2V replace the BM5-Board
b) 3.2V Present. Go to Step 4
4) Check for LD voltage CN6701/pin 26 on IP5Z-Board
a) No 11V replace the Balancer Board
b) 11V Present replace the IP5Z-Board
5) Check Balancer Board Feedback (FB) voltage CN6701/pin 2
NOTE: Use a DMM or Oscilloscope to measure the ACrms voltage level or wavform level.
a) No FB replace the Balancer Board
b) FB Present. Go to Step 6
6) Check the condition of the individual HV Balancer Board Outputs.
a) Excessive High Level at One or More HV outputs replace LCD Panel Assembly.
b) Excessive Low Level at One or More HV outputs. replace Balancer Board.
c) All HV Output Levels within Spec. Replace BM-Board
7X Blink Pattern (Temperature
Failure)
These models do not display a temperature warning OSD dialogue box before shutting OFF and going into a 7X Timer/PIC OFF LED blink pattern.
The main objective when a 7X blink pattern occurs is to determine which of the following possible defects is causing the excessive temperature condition.
# Excessively Ambient Room Temperature
# Dust or Debris Blocking the TV Ventilation Apertures
# Defective Temperature Sensor IC3007
# Defective Main Microprocessor IC3011
The fi rst step is to notice how long it takes the TV to shut OFF and trigger
a 7X blink protection mode.
If the TV has an actual excessive temperature condition it will take a considerable period of time to shut OFF and indicate a 7X blink protection mode. This is because it will take time for the TV to heat up and for the temperature sensor to detect the excessive temperature and shut the TV OFF.
If the TV takes a considerable period of time to shut OFF check the following items:
# The TV should not be located too close to any heating elements.
# There should be at least 4 inches of clearance completely around the TV to ensure adequate ventilation.
# Check that all vented areas on the TV are clear of all Dust and Debris.
If the TV shuts OFF immediately (Not an Actual Excessive Temperature Condition) after Power-ON then one of the following components has failed.
# Main Microprocessor IC3011 (BM5-Board)
# Temperature Sensor IC3007 (BM5-Board)
These models do not display a temperature warning OSD dialogue box before shutting OFF and going into a 7X Timer/PIC OFF LED blink pattern.
The main objective when a 7X blink pattern occurs is to determine which of the following possible defects is causing the excessive temperature condition.
# Excessively Ambient Room Temperature
# Dust or Debris Blocking the TV Ventilation Apertures
# Defective Temperature Sensor IC3007
# Defective Main Microprocessor IC3011
The fi rst step is to notice how long it takes the TV to shut OFF and trigger
a 7X blink protection mode.
If the TV has an actual excessive temperature condition it will take a considerable period of time to shut OFF and indicate a 7X blink protection mode. This is because it will take time for the TV to heat up and for the temperature sensor to detect the excessive temperature and shut the TV OFF.
If the TV takes a considerable period of time to shut OFF check the following items:
# The TV should not be located too close to any heating elements.
# There should be at least 4 inches of clearance completely around the TV to ensure adequate ventilation.
# Check that all vented areas on the TV are clear of all Dust and Debris.
If the TV shuts OFF immediately (Not an Actual Excessive Temperature Condition) after Power-ON then one of the following components has failed.
# Main Microprocessor IC3011 (BM5-Board)
# Temperature Sensor IC3007 (BM5-Board)
In either case the BM5-Board must be replaced
to fi x the problem.
8X Blink Pattern (Audio Failure)
The 8X blink protection mode occurs when one of the audio outputs is shorted, a DC voltage level is present on the outputs, or the AU15V is missing. In most cases an audio problem will exist within the audio circuit, which is located completely on the BM5-Board. However, before replacing the BM5-Board perform the following checks.
# Check the AU15V at CN4001/pin 1 on the BM5-Board. If 15V is present replace the BM5-Board. If the 15V is missing troubleshoot the IP5Z board.
# Check the speakers and/or speaker connections for damage. The speakers should measure 8 ohms. Check all connectors and wiring for damage. Replace and repair components where needed. If the TV still shuts OFF (8X) then the problem is with the Main microprocessor, and consequently, the BM5-Board must be replaced.
Video Troubleshooting
IMPORTANT: Before proceeding with the following video troubleshooting procedures it is assumed that the TV is turning on with the Green Power LED is illuminated steady and audio is okay. If a Video and Audio failure is occurring then there is most likely a Power Supply defect and in most cases a protection mode will be activated.
The only exception to this rule would be if the No Audio & No Video is occurring on a single input. In this case the defect may exist in the external device.
When a video problem occurs you will experience one of the two following symptoms.
Input Status:
# Missing or Distorted Video on All Inputs
8X Blink Pattern (Audio Failure)
The 8X blink protection mode occurs when one of the audio outputs is shorted, a DC voltage level is present on the outputs, or the AU15V is missing. In most cases an audio problem will exist within the audio circuit, which is located completely on the BM5-Board. However, before replacing the BM5-Board perform the following checks.
# Check the AU15V at CN4001/pin 1 on the BM5-Board. If 15V is present replace the BM5-Board. If the 15V is missing troubleshoot the IP5Z board.
# Check the speakers and/or speaker connections for damage. The speakers should measure 8 ohms. Check all connectors and wiring for damage. Replace and repair components where needed. If the TV still shuts OFF (8X) then the problem is with the Main microprocessor, and consequently, the BM5-Board must be replaced.
Video Troubleshooting
IMPORTANT: Before proceeding with the following video troubleshooting procedures it is assumed that the TV is turning on with the Green Power LED is illuminated steady and audio is okay. If a Video and Audio failure is occurring then there is most likely a Power Supply defect and in most cases a protection mode will be activated.
The only exception to this rule would be if the No Audio & No Video is occurring on a single input. In this case the defect may exist in the external device.
When a video problem occurs you will experience one of the two following symptoms.
Input Status:
# Missing or Distorted Video on All Inputs
# Missing or Distorted Video on Individual
Inputs Video Anomaly:
# Poor Detail
# Moving Video Distortion (e.g. Bars)
# Static H/V Lines (black, white, or color)
# White Balance
# Gamma
The main objective when troubleshooting one of the previously listed symptoms is to determine if the defect exists in the following sections of the TV system.
# LCD Panel Assembly (Includes the TCON Board)
# BM5-Board
No Video (All Inputs)
If the video is completely missing, you will fi rst use the On-Screen-Displays (OSD) to possibly isolate the defect to the BM5-Board or the LCD Panel
Assembly.
On-Screen Displays (OSD)
# “BRAVIA” Logo OSD
# USER Menu OSD
If either the BRAVIA Logo OSD or USER Menu OSD can be displayed then the LCD Panel assembly is okay, and you can safely assume the defect exists on the BM5-Board. However, if the BRAVIA Logo OSD or USER
Menu OSD cannot be displayed you need to do further troubleshooting because either IC7000 is not sending the OSD or the LCD Panel assembly is not able to display the OSD.
The BRAVIA Logo OSD is inserted into the video at the very end of the Video path. The USER Menu is inserted into the video towards the beginning of the video path. Both are inserted within the Xillion IC7000 on the BM5-board.
# Poor Detail
# Moving Video Distortion (e.g. Bars)
# Static H/V Lines (black, white, or color)
# White Balance
# Gamma
The main objective when troubleshooting one of the previously listed symptoms is to determine if the defect exists in the following sections of the TV system.
# LCD Panel Assembly (Includes the TCON Board)
# BM5-Board
No Video (All Inputs)
If the video is completely missing, you will fi rst use the On-Screen-Displays (OSD) to possibly isolate the defect to the BM5-Board or the LCD Panel
Assembly.
On-Screen Displays (OSD)
# “BRAVIA” Logo OSD
# USER Menu OSD
If either the BRAVIA Logo OSD or USER Menu OSD can be displayed then the LCD Panel assembly is okay, and you can safely assume the defect exists on the BM5-Board. However, if the BRAVIA Logo OSD or USER
Menu OSD cannot be displayed you need to do further troubleshooting because either IC7000 is not sending the OSD or the LCD Panel assembly is not able to display the OSD.
The BRAVIA Logo OSD is inserted into the video at the very end of the Video path. The USER Menu is inserted into the video towards the beginning of the video path. Both are inserted within the Xillion IC7000 on the BM5-board.
Perform the following steps to quickly determine if the BM5-Board or LCD Panel
is causing a “No Video” on all inputs condition.
1) Check for BRAVIA Logo OSD when the TV first turns ON
a) BRAVIA OSD Displays. Go to Step 2
b) BRAVIA Does Not Display. Go to Step 3
2) Check for USER Menu OSD Display
a) USER Menu Displays. Replace BM5-Board
b) USER Menu Does Not Display. Go to Step 3
3) Check for 12V at CN9102/pin 47 to 51
a) No 12V. Replace BM5-Board
b) 12V Present. Go to Step 4
4) Check LVDS Cable Video Signal Levels.
1) Check for BRAVIA Logo OSD when the TV first turns ON
a) BRAVIA OSD Displays. Go to Step 2
b) BRAVIA Does Not Display. Go to Step 3
2) Check for USER Menu OSD Display
a) USER Menu Displays. Replace BM5-Board
b) USER Menu Does Not Display. Go to Step 3
3) Check for 12V at CN9102/pin 47 to 51
a) No 12V. Replace BM5-Board
b) 12V Present. Go to Step 4
4) Check LVDS Cable Video Signal Levels.
a) LVDS Video Signal(s) Low or Missing.
Replace BM5- Board
b) LVDS Video Signals Okay. Replace LCD Panel Assembly
Distorted Video (All Inputs)
The two components common to all inputs are as follows.
# LCD Panel Assembly
# BM5-Board
The following paragraphs discribe how the LCD Panel Assembly and BM5-Board each have their unique affect on video processing and what affects they have in common. Knowing how each componet affects the video can be very helpful in troubleshooting a distorted video condition. A quick test to determine if the BM5-Board or LCD Panel is defective is to change the panel aspect ratio. If the distortion follows the video then the BM5-Board is causing the distortion. If the distortion remains stationary after changing the aspect ratio then the LCD Panel assembly is causing the distortion.
b) LVDS Video Signals Okay. Replace LCD Panel Assembly
Distorted Video (All Inputs)
The two components common to all inputs are as follows.
# LCD Panel Assembly
# BM5-Board
The following paragraphs discribe how the LCD Panel Assembly and BM5-Board each have their unique affect on video processing and what affects they have in common. Knowing how each componet affects the video can be very helpful in troubleshooting a distorted video condition. A quick test to determine if the BM5-Board or LCD Panel is defective is to change the panel aspect ratio. If the distortion follows the video then the BM5-Board is causing the distortion. If the distortion remains stationary after changing the aspect ratio then the LCD Panel assembly is causing the distortion.
AUDIO TROUBLESHOOTING
The first step when a “Missing or Distorted Audio” defect occurs is to determine if audio is missing or distorted on all audio input sources or only on one or a select number of audio input sources.
Input Status:
# Missing or Distorted Audio on All Inputs
# Missing or Distorted Audio on Individual Inputs
Missing or Distorted Main Speaker Audio - All Inputs
In this case, the most likely defective is the BM5-Board. Before you replace the BM5-Board perform the following test procedures to confirm the actual defective component.
1) Check for audio at the FIX, HEADPHONE, or DIGITAL Audio Outputs
a) No or Distorted Audio (Replace BM5-Board)
b) Audio Present & Undistorted. Go to Step 2
2) Check for AU15V at CN4001/pin 1 on BM5-Board
a) No AU15V replace IP5Z Board
b) AU15V Present replace BM5-Board
Missing or Distorted Main Speaker Audio - Individual Inputs
If only one or a select number of input sources are experiencing a problem, then the individual inputs must be checked separately. The external devices and their associated cables connected to the faulty input should be checked first.
The first step when a “Missing or Distorted Audio” defect occurs is to determine if audio is missing or distorted on all audio input sources or only on one or a select number of audio input sources.
Input Status:
# Missing or Distorted Audio on All Inputs
# Missing or Distorted Audio on Individual Inputs
Missing or Distorted Main Speaker Audio - All Inputs
In this case, the most likely defective is the BM5-Board. Before you replace the BM5-Board perform the following test procedures to confirm the actual defective component.
1) Check for audio at the FIX, HEADPHONE, or DIGITAL Audio Outputs
a) No or Distorted Audio (Replace BM5-Board)
b) Audio Present & Undistorted. Go to Step 2
2) Check for AU15V at CN4001/pin 1 on BM5-Board
a) No AU15V replace IP5Z Board
b) AU15V Present replace BM5-Board
Missing or Distorted Main Speaker Audio - Individual Inputs
If only one or a select number of input sources are experiencing a problem, then the individual inputs must be checked separately. The external devices and their associated cables connected to the faulty input should be checked first.
Substitute a known good device and cable on
the suspected faulty 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. However, if the external device and cables
are okay, then the next step is to replace the common board or module
associated with that particular input source.
For example, consider the symptom of all or only one or two of the Composite 1, 3 or NTSC inputs are faulty. Logically the only device that could cause this symptom is the switcher IC2014 on the BM5-Board. The most likely problem is one or more of the switcher inputs are defective. In this case, replace the BM5-Board. Another example would be missing or distorted audio on one or both HDMI input only. The only component that would affect only the HDMI audio inputs is the HDMI receiver IC5801 on the BM5-Board. Therefore, replacing the BM5-Board should fix this problem.
For example, consider the symptom of all or only one or two of the Composite 1, 3 or NTSC inputs are faulty. Logically the only device that could cause this symptom is the switcher IC2014 on the BM5-Board. The most likely problem is one or more of the switcher inputs are defective. In this case, replace the BM5-Board. Another example would be missing or distorted audio on one or both HDMI input only. The only component that would affect only the HDMI audio inputs is the HDMI receiver IC5801 on the BM5-Board. Therefore, replacing the BM5-Board should fix this problem.
TCON BOARD FAULT SYMPTOMS
