Technical description and composition of the PANASONIC TX-L42DT50 TV, panel type and modules used. The composition of the modules.PANASONIC LED
Model: TX-L42DT50 TX-L42DT50E
Chassis / Version: LA35
Panel: VVX42F130B20
LED backlight: NLAW20163L, NLAW20163R
LED driver (backlight): integrated into PSU
PWM LED driver: BD9225KV
Power Supply (PSU): CT31002 U84PA-E0011286H
PWM Power: MIP2K4 (Stb), 2A100 (PFC), FSFR2100XSL
MainBoard: TNPH0993
IC MainBoard: ZWC0250, 29F4G08ABADA, TMDS361B, CY7C65632
Tuner: ENVS9302D5F
TX-L42DT50 Specifications
PANASONIC TX-L42DT50
General recommendations for TV LCD LED repair
Possible malfunctions
- The PANASONIC TX-L42DT50 TV does not turn on, does not respond to the remote control and control panel buttons, does not light or blink indicators.
In some of these cases, the main switching power supply, the CT31002 module, is faulty. It is necessary to make sure that its output voltages are present and, if they are completely absent, check the power switches and rectifier diodes for a possible short circuit.
In case of any breakdowns in the secondary circuits, the converter can operate in an emergency mode of a short circuit, and in the event of a short circuit in the power elements of the primary circuit, the mains fuse or the current sensor in the source of the key is often cut off.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements, which can disable it in key mode, or provoke an excess of the maximum current or voltage values. These can be circuits supplying a PWM controller, damper or frequency setting circuits, or OOS (negative feedback) elements in the stabilization circuit. PWM controllers (PWM) MIP2K4 (Stb), 2A100 (PFC), FSFR2100XSL, in the absence of external damage and a short circuit between the terminals, are checked by replacing them with known good ones.
- There is no image, there is sound, it reacts to the remote control. Or, immediately after switching on for a second, the image may appear and immediately disappear.
The malfunction in most of such cases is found in the nodes and elements of the LED panel backlight. The reason may be both in the power supply of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
It is impossible to check the LED bars for a break without disassembling the panel with a multimeter or tester. For these purposes, it is necessary to open all series-connected PN junctions and a voltage of the order of tens of volts is required, and ideally a current source. Having disassembled the panel, it is necessary to check each LED separately. Chinese multimeters tend to lightly light one 3-volt LED in the forward direction. In the case of using dual 6-volt LEDs, the PN junction of its protective zener diode can serve as an indicator of serviceability. In faulty LEDs, the zener diode will either be cut off, or pierced in the K / Z.
- The indicator blinks or is on constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the TNPH0993 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). If it is not possible to replace the MB (SSB) board, it is necessary to check the serviceability of its elements - ZWC0250, 29F4G08ABADA, TMDS361B, CY7C65632. Defective components must be replaced.
If there is no reception of television channels, but the TV is working properly from external devices, first of all, you need to check the supply voltage of the ENVS9302D5F tuner and update the software. I2C communication pulses must be monitored with an oscilloscope.
If the PANASONIC TX-L42DT50 has no picture, but there is sound, often the VVX42F130B20 display backlight simply does not work. Moreover, in LED TVs, the LEDs inside the panel usually fail, less often the LED driver.
In such cases, you can see a barely noticeable image with a successful hit of external light on the screen.
Replacing the LEDs requires disassembling the VVX42F130B20 LCD panel - a process that requires experience and qualifications from the master. We do not recommend doing such work on your own to the owners of TVs and craftsmen who do not have experience in repairing LCD panels
If there is no image, and the backlight is on, the screen becomes slightly lighter when turned on, and in an open TV you can see light through the holes in the panel case.
In this case, the panel may also be faulty - damage to the strips, loops, for example, as a result of moisture ingress after unsuccessful washing of the screen, the T-CON (Timing Controller) board may be faulty. But the main board MainBoard TNPH0993 often turns out to be faulty, a software failure is also possible.
Then, first of all, it is necessary to check the panel supply voltage, fuses on the T-CON board, as well as the supply and reference voltages of the column and line drivers - VGH, VGL, Vcom.
If these measurements are within normal limits, it is necessary to trace the passage of LVDS signals from the MainBoard TNPH0993 with an oscilloscope, as well as synchronization signals to the loops with drivers.
Flooded or unsuccessfully washed screens of LED TVs can be restored, in about half of the cases, usually if significant damage has not formed in the loops and panel strips.
Attention to TV owners! Attempts to repair PANASONIC TX-L42DT50 yourself are not recommended by the manufacturer and can lead to serious negative consequences!
DOWNLOAD SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> PANASONIC TX-L42DT50 Chassis LA35 for TX-L42DT50E, TX-L47DT50
The appearance of MainBoard TNPH0993 is shown in the figure below:TNPH0993
The main features of the PANASONIC TX-L42DT50 device:
Installed matrix (LED-panel) VVX42F130B20.
To power the backlight LEDs, a converter combined with a power supply is used, controlled by a BD9225KV PWM controller.
The formation of the necessary supply voltages for all nodes of the PANASONIC TX-L42DT50 TV is carried out by the CT31002 power module, or its analogs using the MIP2K4 (Stb), 2A100 (PFC), FSFR2100XSL microcircuits.
MainBoard - the main board (motherboard) is a TNPH0993 module, using chips ZWC0250, 29F4G08ABADA, TMDS361B, CY7C65632 and others.
Tuner ENVS9302D5F provides reception of television programs and tuning to channels.
TV PANASONIC TX-L42DT50 with LCD VVX42F130B20, 42 "(107 cm) diagonal in 16: 9 format. The technology of manufacturing the screen of this TV model is realized with LED backlighting.
There is support for 3D images with active (shutter) separation technology of the right and left channels.
The VVX42F130B20 panel and TNPH0993 motherboard firmware provide HD and Full HD viewing at 1920x1080 pixels in 1080p (Full HD) graphics.
The TX-L42DT50 is equipped with SMART software, built-in applications and Internet connectivity. Internet connection can be made via Wi-Fi wireless connection. The input analog video signal can be processed in PAL, SECAM, NTSC systems. Graphic processing and formation of a digital signal picture occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Multimedia file formats supported by the video processor: MP3, WMA, MPEG4, MKV, JPEG. Stereo sound and the required sound output is realized by two built-in speakers. Uses NICAM stereo signal system and Sound Surround function.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, SCART, RGB, VGA, HDMI x4, USB x3, Ethernet (RJ-45), Wi-Fi. A headphone output is provided for individual listening. To connect a computer or laptop, a VGA (D-Sub 15) connector is used, which supports resolutions: 1024x768, 1280x1024, 1360x768, 1920x1080.
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 116 watts.
Dimensions: with stand 958x615x258 mm, without stand 958x569x27 mm.
TV weight: with stand: 14.5 kg, without stand: 11 kg.
Attention! The VVX42F130B20 panel of the PANASONIC TX-L42DT50 LED TV is its most expensive element.
Do not allow any impact on the glass and pressure on the screen surface to avoid damage to the LED panel!
Liquid spillage on the screen is unsafe. Sometimes one drop is enough if it drips down the glass onto the cables to make the TV unrepairable.
