Technical description and composition of the PANASONIC TX-55FXR740 TV, panel type and modules used. The composition of the modules.PANASONIC LED
Model: TX-55FXR740
Chassis / Version: LA76 // KM42
Panel: LC550EGE (AL) (A1)
T-CON: 6870C-0780A
LED driver (backlight): integrated into PSU
PWM LED driver: BD9479FV
MOSFET LED driver: P17F28HP2
Power Supply (PSU): TNPA6704 1P // TNPA6397 3P
PWM Power: FA5696N, FA6B02N, BD9E102FJ (STB)
MOSFET Power: TK10A60W, TK7A60W
MainBoard: TNPH1197 1A // TNPH1196 1A
IC MainBoard: CPU, eMMC, DRAM, AUDIO, DC / DC
Tuner: 24H133A J3ACZAC00005
TX-55FXR740 Specifications
PANASONIC TX-55FXR740
General recommendations for TV LCD LED repair
Possible malfunctions
- PANASONIC TX-55FXR740 TV does not turn on. There are no signs of operability. The indicators on the front panel do not light or blink, the TV does not respond to control buttons.
Often in such cases the TNPA6704 power supply module is faulty. It is necessary to measure its output voltages, and if they are absent (full or partial), check the serviceability of the power switches (TK10A60W, TK7A60W) of the converters and rectifier diodes for a possible short circuit.
In case of breakdowns of semiconductors in the secondary circuits of any converter, as a rule, it can operate in an emergency mode of short circuit without output voltages, and with a short circuit in the elements of the primary circuit, the mains fuse most often breaks off immediately and less often the current sensor in the source of the key.
Mos-Fet power switches used in switching power supplies sometimes fail due to a malfunction of any other elements that can disable it in the key mode, or create an excess of the maximum permissible key parameters. These can be elements supplying a PWM regulator, frequency setting or damper circuits, or elements of negative feedback in the stabilization circuit. PWM controllers FA5696N, FA6B02N, BD9E102FJ (STB), in the absence of visible damage or outright short circuits between the terminals, are checked by replacing them with new ones, or known to be working properly.
- There is no picture, but there is sound, it reacts to the remote control. Or the image appears when turned on and disappears immediately
Often in such cases, there is no backlighting of the LED panel. Often the reason is a malfunction of the LEDs (open circuit, short circuit ...), or the connectors of the strips (strings), less often the LED driver turns out to be faulty.
It is impossible to detect an open circuit in the LED line without disassembling the panel with a simple multimeter. The LEDs are connected in series and a voltage of several tens of volts is required to open their junctions. Ideally, a current source is suitable for such purposes. You can open the panel and check each LED separately. Usually, Chinese multimeters lightly light up one 3-volt LED if you connect the probes to it in the forward direction (red probe to the anode, black to the cathode). For dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of the LED health. In the event of a malfunction of the LED, its zener diode will either be cut off or pierced in the K / Z.
- The TV does not turn on, the indicator signals the standby or operating mode, or blinks.
Repair or diagnostics of the TNPH1197 motherboard should begin with checking the stabilizers and power converters necessary to power the microcircuits and the matrix. If necessary, you should update or replace the software (software). Complex repair of MB (SSB) is possible only in a service center with the necessary equipment. Checking or replacing elements of CPU, eMMC, DRAM, AUDIO, DC / DC requires the necessary training and professional skills in repairing modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by the warm-up method.
Malfunction of the tuner 24H133A J3ACZAC00005 is established after checking the software and all supply voltages at its outputs. The data exchange of the tuner with the processor via the I2C bus can be monitored with an oscilloscope.
Users and owners of TVs should remember that attempts to self-repair the PANASONIC TX-55FXR740 TV without the appropriate qualifications and the necessary experience can lead to serious negative consequences!
DOWNLOAD SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> PANASONIC TX-55FXR740 Chassis LA76 for models TX-55FX740E, TX-55FXR740
DOWNLOAD SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> TNPA6704 Power supply
DOWNLOAD SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> TNPA6397 Power supply
The appearance of the MainBoard TNPH1197 is shown in the figure below:
TNPH1197
External view of the power supply
The main features of the PANASONIC TX-55FXR740 device:
Installed matrix (LED panel) LC550EGE (AL) (A1).
Matrix control uses the Timing Controller (T-CON).
A converter combined with a power supply is used to power the backlight LEDs, and is controlled by a BD9479FV PWM controller. The keys of the P17F28HP2 type are used as power elements of the LED driver.
The formation of the necessary supply voltages for all nodes of the PANASONIC TX-55FXR740 TV is carried out by the TNPA6704 power module, or its analogs using the FA5696N, FA6B02N, BD9E102FJ (STB) microcircuits and power switches of the TK10A60W, TK7A60W type.
MainBoard - the main board (motherboard) is a TNPH1197 module using CPU, eMMC, DRAM, AUDIO, DC / DC and others.
Tuner 24H133A J3ACZAC00005 provides reception of television programs and tuning to channels.
PANASONIC TX-55FXR740 TV with LCD LC550EGE, diagonal size 54.6 "(139 cm) 16: 9 format. The required screen brightness of 500 cd / m² is provided by LED backlighting. The LED panel of this TV is equipped with LED edge lighting Edge LED.
Display LC550EGE The software of the TNPH1197 board allows viewing images in high quality UHD 4K at a resolution of 3840x2160 pixels in the graphics standard 4K UHD, HDR. Graphic image processing is carried out using modern High Dynamic Range (HDR) technologies with an extended range of brightness gradations.
The TX-55FXR740 is equipped with SMART software, built-in applications and Internet connectivity. Internet connection can be made via Wi-Fi wireless connection. Multimedia file formats supported by the video processor: MP3, WMA, MPEG4, HEVC (H.265), MKV, JPEG.
The power of the acoustic audio system is 20 W (2x10 W), provided by two speakers. Uses NICAM stereo signal system and Sound Surround function.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, HDMI x3, USB x3, Ethernet (RJ-45), Bluetooth, Wi-Fi 802.11ac. A headphone output is provided for individual listening.
The digital tuner is capable of receiving terrestrial and cable channels in the DVB-T MPEG4, DVB-C, DVB-T2, DVB-S2 standards.
The power consumed by the TV in operating mode from the network is 196 watts.
Dimensions: with stand 1234x775x254 mm, without stand 1234x717x55 mm.
TV weight: with stand: 32.5 kg, without stand: 28 kg.
Attention! The LC550EGE (AL) (A1) panel of the PANASONIC TX-55FXR740 LED TV is the most expensive element.
Do not allow any impact on the glass and pressure on the screen surface to avoid damage to the LED panel!
It is unsafe for liquid to spill onto the screen. Sometimes one drop is enough if it drips down the glass onto the cables to make the TV unrepairable.
