Monday, July 08, 2019

Panasonic Smart Viera LED LCD TVs, working principle, Troubleshooting, LED blinking codes details


Models TC-L47DT50, TC-L55DT50, TC-L42E50, TC-L47E50, TC-L55E50, TC-L42ET5, TC-L47ET5, TC-L55ET5, TC-L47WT50, TC-L55WT50
ET5, DT50 and WT50 Series-LCD HD/FHD TV 2012 LCD TV
A cell phone may be used to detect the TV’s Bluetooth transmission. The name “Panasonic Viera” is displayed on the cell phone when the 3D Bluetooth signal is discovered.
Not all iPhones and smartphones are capable of discovering the Panasonic Bluetooth signal. The self-check procedure on the left is most reliable.
To access the self-check screen, simultaneously hold down the Volume Down button of the TV and the OK button on the remote control for a few seconds.
The absence of the Bluetooth and WIFI module are indicated as follows:
Bluetooth = Error 01 in Red
WIFI = Long dash in red.
Do not use 3D bluetooth transmission in hospital or other medical facilities.
Radio waves from 3D bluetooth transmission may cause interference of medical equipment.
Do not use 3D bluetooth transmission nearby automatic control equipment, like an automatic door, a fire alarm apparatus, etc.
Radio waves from 3D bluetooth transmission may cause interference of automatic control equipment.
Keep 3D bluetooth transmission more than 22 cm (9 in.) away from the implant of cardiac pacemaker, or similar implantable medical equipment, at all times.
Radio waves from 3D bluetooth transmission may affect implantable cardiac pacemaker or similar equipment operations.
Viewing 3D images
1.A 3D Blu-ray disc, played on 3D capable Blu-ray player/recorder that is connected via HDMI cable.
2. 3D TV broadcast (program)
3. 3D Photo and 3D Movie taken by LUMIX/Camcorder.
4. 3D game played on 3D capable video game console, connected via HDMI cable.
Stand by/Start-up Operation (P/A board)
When the TV is plugged in, the power board outputs 5V for standby power. Upon receiving this voltage, the micro (IC8000) outputs the TV_SUB_ON command.
When the power supply receives the TV_SUB_ON signal, it outputs 2 different voltages:
 P15V to the A board on pins 1, 2, and 3 of connector P2.
 24V to the LED backlight power board on pins 7, 8, and 9 of connector P4. This voltage is not used at plug-in.
When the power-on button is pressed and the A board is ready to turn on the display, IC8000 of the A board outputs the Backlight-on command to LCD Module.
Start up operation _ Step 1
When the TV is plugged in, the rectifier circuit produces a DC voltage that travels through the PFC circuit directly to the power switches Q7301 and Q7302. A separate DC voltage, approx. 40V, produced by D7104 and D7105 serves as start-up voltage to pin 1 of the oscillator IC7301. When the voltage on pin 1 rises up to a predefined value, IC7301 starts to oscillate and output switching pulses to Q7301 and Q7302. As current flows through the winding of T7301, output voltages are generated by the transformer. One of these voltages, VCC, is used to power pin 10 of IC7301 .
When the power supply starts up, 6V is created by D7407/C7514. This voltage goes to IC7502 which is a 5V regulator. The start command for this regulator originates at pin 3 of IC7301.
This pin is internally grounded in normal state and the information is carried to the secondary side by PC7303. Finally there is around 2.4V on pin 3 of IC7502 to start its operation. Then 5V is output at pins 1 and 2 of the IC.
This voltage (STB5V) is provided to the A board via pin 5 of connector P2.
So when the TV is plugged in, STB5V is provided to A board without an external trigger signal.
Start up operation _ Step 2
The STB5V from pin 5 of connector P2 is applied to the Analog ASIC (IC5000) to supply power to the Main CPU/PEAKS LD4 (IC8000) on the A board. The Analog ASIC (IC5000) converts the STB5V to STB3.3V and STB1.2V. These 2 voltages energize and prepare the microprocessor (CPU) for program execution. The STB3.3V from the Analog ASIC (IC5000) is also applied to the remote control receiver and the power LED on the K board through pins 5 and 10 of connector A10.
Upon energizing, IC8000 automatically outputs the TV _SUB_ON command for approximately 12 seconds. This command triggers the output of the P15V source (not shown in the drawing) to the A board, but the red LED does not light.
The A board performs a self-check operation to determine its communication status. If a defect is encountered, the unit shuts down and possibly displays a blink code. If all is well, the unit goes to the standby mode.
When the power on command from the power switch, the remote control receiver or Viera Link is provided to IC8000 PEAKS LD4, the “TV_SUB_ON” command (2.4V) is output. The “command is provided to the power supply board via pin 7 of connector P2.
Start up operation _ Step 3
When the power board receives the TV_SUB_ON signal from IC8000 via pin 7 of connector P2, it outputs 2 different voltages:
1.P15V to the A board on pins 1, 2, and 3 of connector P2.
2.24V to the LED backlight power board on pins 7, 8, and 9 of connector P4.
This command is carried to the primary side of the power supply by PC7302. This voltage turns on the transistor Q7303 to provide a reference voltage from pin 6 to pin 5 of IC7301.  Therefore the operation of IC7301 changes the switching frequency from standby state to increase the output voltages.
The TV_SUB_ON command also turns on Q7202 to provide power and turn on the PFC circuit. As a result, the PFC starts to operate and the output voltages from the transformer T7301 start to rise until the moment IC7401 starts to operate. This IC monitors the 16V output on the secondary side of the power supply. The output of IC7401 is provided to pin 4 of IC7301 by PC7301. IC7301 adjust the switching frequency by this feedback signal. The circuit is designed to maintain a stable DC output of the power supply.
The TV_SUB_ON signal also switches on the transistors Q7402 and Q7403 to output the P15V and 24V output voltages to other boards.
The 24V is provided to the LCD Module ( LED Backlight Power Supply).
The P15V is provided to the A board.
Start up operation _ A board (SUB voltages)
The P15V from the P board enters the A board via pins 1, 3 and 5 of connector A02. It is applied to the Analog ASIC IC5000 and other ICs (Voltage regulators) to generate the SUB-Voltages used for signal processing operation.
The SUB1.1V, 1.5V, 1.8V, 3.3V, 5V, HDMI3.3V and USB5V are created.
Each voltage regulator is activated by a DCDCEN command created from the P15V source.
So the presence of the P15V source on the A board causes each of the SUB-voltage regulator ICs to output a DC voltage.
Start up operation _ A board (OVP circuit)
The Sub voltages are monitored for over-voltage condition. If any of these voltages increases above a predetermined level, the OVP circuit will be triggered by getting pin 7 of IC5000 to go high.
When pin 7 goes high, the TV_SUB_ON voltage connected to pin 8 is grounded. This disables the circuit that generates the P15V and 24V on the power supply.
If any abnormality occurs with P15V, the DCDCEN circuit inside IC5000 provides a DC output to turn on the switch at pin 11. This in turn disables the output of the SUB-Voltage regulator ICs (IC5400, IC5420, IC5440, IC8100 and IC8101).
When an over voltage condition is detected at plug-in the TV becomes completely disabled and the power
LED remains off.
When an over voltage condition is detected at power-on the TV becomes completely disabled and the power
LED remains on.
Start up operation _ A board (PNL,FRC voltage)
The P15V is also used to generate the PNL-Voltage and FRC-Voltages on the A board. IC5000 outputs the Panel VCC On2 signal. IC5300 uses this command to generate the PNL12V.
The PNL12V is provided to the T-con circuit of the LCD Module and ICs (Voltage regulator) to produce FRC-Voltages.
After that, IC8000 outputs the BL_ON command to the LCD Module through the P board. The BL_ON command turns on the LED backlight power supply of the LCD Module. If the backlight power circuit does not work normally, the BL_SOS signal communicates this information to IC8000. At that time, IC8000 stops outputting the TV_SUB_ON signal and blinks the red power LED 1 times.
TC-L47ET5 Connector Voltages)
Video Signal Processing
Video Process
The main function of the A board is to select and process one of the incoming video signals. IC8458 and IC4700 are switches that select USB and HDMI signals. The built-in WiFi module is connected using a USB type terminal.
Video input, Component Video Input, composite video output of the tuner and the other HDMI input are all connected to IC8000 for selection. The IC has interface circuits that converts each input signal into digital RGB . The data selected for viewing is then provided to the RGB process circuit within the same IC for processing.
The RGB Process section of the IC performs all picture control operations such as brightness, contrast, color, tint, etc. On Screen Display data such as channel numbers, Digital TV closed caption, and picture adjustments are mixed with the video data. After the process, LVDS (Low Voltage Differential Signaling) is output to IC9100. IC9100, the FRC (Frame Rate Converter) IC doubles or triples the frame rate to improve focus and eliminate blur.
The output signal is provided to the T-CON for display on the LCD screen.
TC-L47ET5 Upper LVDS Connector
A disconnected upper LVDS connector (TC02A) results in distorted video. The picture appears to be in the background with vertical white line in front.
When troubleshooting a distortion of this type, if the LVDS connector is in place, use the internal pattern generator to determine if the problem is in the A board or the T-CON. A normal T-CON generates pictures that are clean and smooth. Keep in mind, the T-Con is part of the panel. It cannot be replaced in the field.
Lower LVDS connector
When the lower LVDS connector (TC01A) is disconnected, The screen is dark blue with no video.
Use the internal pattern generator to determine if the problem is in the A board or the T-CON. A normal T-CON generates pictures that are clean and smooth. Keep in mind, the T-Con is part of the panel, it cannot be replaced in the field.
Panel Free Run Mode
When a picture problem is encountered, the internal test pattern generator may be used to determine whether the symptom is the result of a defective A board or panel.
The test pattern is displayed:
Panel Drive
1.The panel_VCC_ON command turns on the panel 12V regulator to power the T-CON circuit.
2. The PWM_ENB command turns on the PWM generator to produce the control signal for the LED backlight circuit.
3. The DISPEN command turns on the T-CON circuit to produce the column and row signals to drive the panel.
4. Since the T-CON determines the panel’s drive signals, the Bluetooth Left and Right signals are generated for transmission to the glasses.
5. The LVDS data is the video signal used by the T-CON to produce the column and row signals to drive the panel.
6. The IIC data is the communication line between the T-CON and the Main CPU. Data for the PWM signal is also provided through the IIC line.
7. The LED Driver Control signals, using customer’s OSD, CATS, or artificial intelligence, manipulate the backlight .
47WT50 & 47DT50 LED Backlight Control
The LED driver board receives 66Vdc and 16Vdc from the power supply via connector P4/LD4. The 16V source is used to bias the drive IC, IC9500. The 66V source is used bias the LED. The backlight On command from the same
connector starts the inverter drive signals.
The BL_SOS connection originates at IC8000, the system control IC located on the A board. IC8000 monitors the status of BL_SOS line to determine the state of the LED drive circuit. During normal operation, IC9500 pulls the BL_SOS line
low to inform IC8000 of the illumination of the LED. Should the drive circuit or an LED array inside the panel become defective, the BL_SOS line remains or goes high to inform IC8000 of the condition. The TV shuts down and the power
LED emits a one blink error code.  The LED drive circuit is responsible for delivering the current needed to illuminate the panel’s LEDs. A total of 16 FETs are manipulated on/off by grounding pulses generated within IC9500. To adjust the brightness, the pulses are modulated to control the on and off time of the FETs.
Unlike other models, a PWM_EN command is provided to the T-CON by the system control IC. The actual PWM signals are communicated via the IIC bus line of IC8000. The PWM signals are provided to the LED drive circuit via the
connector LD3.
The 66Vdc source and grounding pulses are delivered to the LEDs via the connectors LD1 and LD4.
When the TV is displaying 3D images, the 3D_ON command is output from IC8000 to change the 66Vdc source of the power supply to 84Vdc.
Note:
 Connector LD1 or LD2 disconnected = Brief (2 seconds) operation with video and sound , then shutdown with one blink of the power LED
Connector LD1 and LD2 disconnected = Brief operation with black screen and sound , then shutdown with one blink of the power LED
Connector LD4 Disconnected = Brief operation with black screen and sound , then shutdown with one blink of the power LED
Connector LD3 Disconnected = Brief operation with black screen and sound , then shutdown with one blink of the power LED.
47DT50 & 47WT50 LED Backlight Control
55WT50 & 55DT50 LED Backlight Control
The LED driver board receives 66Vdc and 16Vdc from the power supply via connector P4/LD4. The  16V source is used to bias the drive IC, IC9500. The 66V source is used bias the LED. The backlight On command from the same connector starts the inverter drive signals.
The BL_SOS connection originates at IC8000, the system control IC located on the A board. IC8000 monitors the status of BL_SOS line to determine the state of the LED drive circuit. During normal operation, IC9500 pulls the BL_SOS line low to inform IC8000 of the illumination of the LED. Should the drive circuit or an LED array inside the panel become defective, the BL_SOS line remains or goes high to inform IC8000 of the condition. The TV shuts down and the power LED emits a one blink error code.
The LED drive circuit is responsible for delivering the current needed to illuminate the panel’s LEDs. A total of 16 FETs (Not shown in the drawing) are manipulated on/off by grounding pulses generated within IC9500. To adjust the brightness, the pulses are modulated to control the on and off time of the FETs.
Unlike other models, a PWM_EN command is provided to the T-CON by the system control IC. The actual PWM signals are communicated via the IIC bus line of IC8000. The PWM signals are provided to the LED drive circuit via the connector LD3.
The 66Vdc source and grounding pulses are delivered to the LEDs via the connectors LD1 and LD4.
When the TV is displaying 3D images, the 3D_ON command is output from IC8000 to trigger the operation of IC9501 and IC9502. These two ICs are part of booster circuits that amplify the VLED source from the power supply to a higher level for 3D operation.
Disconnection of connectors yields the same results as the 47DT50 and 47WT50 models.
Troubleshooting 1 Blink of the Power LED (ET5 Series)
- Normal: BL_ON is high (3.3V) in Standby mode , BL_SOS is low (0V) (power On)
- Error : BL_ON is low (0V) in Standby mode , BL_SOS is high (3.3V) ) (power On)
BL_SOS is generated when a malfunction is detected by the backlight power board. A logic High is sent to IC8000 of the A board via pin 3 of connector P4, pin 10 of connector P2 and pin 4 of connector A02.
Troubleshooting 1 Blink of the Power LED (WT & DT Series)
- Normal: BL_ON is high (3.3V) in Standby mode , BL_SOS is low (0V) (power On)
- Error : BL_ON is low (0V) in Standby mode , BL_SOS is high (3.3V) ) (power On)
BL_SOS is generated when a malfunction is detected by the backlight power board (LD). A logic High is sent to IC8000 of the A board via pin 10 of connector LD4, pin 1 of connector P4, pin 10 of connector P2 and pin 4 of connector A02.
Power LED Blinking codes troubleshooting
Troubleshooting 1 Blink of the Power LED (WT & DT Series)
P15V is supplied by the P board. If P15V is not available the power LED blinks 3 times (quick blink)
Troubleshooting 7 Blinks of the Power LED
This defect can only be caused by the A board.
IC5400 uses the P15V source to produce SUB3.3V.
If SUB3.3V is not detected by IC8000, the LED indicator will blink 7 times. This voltage is only available when IC5400 is activated by the DCDCEN command sent from IC5000.
Troubleshooting 9 Blinks of the Power LED (ET5 Series)
The audio amplifier is powered by the P15V from the P board. If the amplifier works abnormally due to a short-circuit or an overload by one of the speakers, the SOUND_SOS signal will go high level and be detected by IC8000. The TV
shuts down and the power LED blinks 9 times.
Troubleshooting 9 Blinks of the Power LED (DT & WT Series)
The audio amplifiers are powered by the P15V from the P board. If the amplifiers work abnormally due to a short-circuit or an overload by one of the speakers, the SOUND_SOS signal will go high level and be detected by IC8000.
The TV shuts down and the power LED blinks 9 times.
Troubleshooting 10 Blinks of the Power LED
Using the P15V source, IC5300 produces and regulates the PNL12V. If the voltage PNL12V is not detected, the unit shuts down and the LED indicator blinks 10 times. This voltage is only available when IC5300 is activated by the PANEL_VCC_ON command sent from IC8000.
The Power LED Remains in Standby Mode
If one of regulated voltages (P15V, SUB5V, SUB3.3V, SUB1.5V, SUB1.1V, USB5V) becomes excessive, the OVP circuit outputs a High to IC5000 to start the shutdown process. The TV_SUB_ON command goes low to place the TV in standby mode. The power LED indicator turns off. After unplugging and reconnecting the TV to the AC outlet, after power on, the screen may turn on for a short time and then goes back to standby mode.
The LED backlight does not turn on
The BL_PWM signal controls the brightness of the LED backlight. It is a PWM waveform sent by IC8000 of the A board.
This BL_PWM has an amplitude of 3.3V and a frequency of 120Hz.
- In standard picture mode, the average voltage of the BL_PWM signal is about 2.5V (about 80% ON, 20% OFF).
- In vivid picture mode, the BL_PWM signal has a maximum voltage of 3.3V (100% ON).
The BL_PWM voltage varies with brightness, the darker the screen, the lower the BL_PWM voltage.
If the BL_PWM voltage is maximum in vivid picture mode, but the LED backlight brightness is still significantly darker than that of normal condition, the Panel Module is damaged.