Friday 4 September 2020

REPAIRING / SERVICING TV PANASONIC TX-R26LE7

Technical description and composition of the PANASONIC TX-R26LE7 TV, panel type and modules used. The composition of the modules.
PANASONIC
Model: TX-R26LE7 TX-26LE7
Chassis / Version: GLP21M
Panel: LTA260W2-L12
T-CON: 260W2P4LV0.2
Inverter (backlight): INVUT260A REV0.9 LH41-00240H
PWM Inverter: BD9883AF
Power Supply (PSU): TNP0EP009 P 9
PWM Power: MR4040
MOSFET Power: integrated
MainBoard: TNP0EA009 A 9
IC MainBoard: cpu: VCT69 ***, EEPROM: 24C32 HDMI: SII9023
Tuner: TXN / B10AGNE
Control: IR: TNP0EV009
TX-26LE7 Specifications
PANASONIC TX-R26LE7
General recommendations for TV LCD repair
Possible malfunctions
- PANASONIC TX-R26LE7 does not turn on and does not show any signs of operability at all. Does not blink indicators and does not respond to control buttons.
Most likely, in this case, the main switching power supply (SMPS) TNP0EP009 is faulty. Its output voltages should be measured, and in their absence, check the serviceability of the power switches (integrated) converters and rectifier diodes for the probability of 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.
Breakdown of Mos-Fet switches used in switching power supplies is often caused by malfunctions of other elements, for example, in the power supply circuit of the PWM controller, in frequency setting or damper circuits, as well as in negative feedback stabilization. Microcircuits PWM (PWM) MR4040 are usually checked by replacing them with new ones, or knowingly working.
- There is no picture, but there is sound and reaction to the remote control. Or, for a second, the image may appear immediately after switching on.
A defect can be caused by problems in the nodes or elements of the display backlight, or in the power supply of lamps or the inverter.After checking all the electrolytic capacitors of the filters that are involved in the power supply of the inverter, ring the power switches in its converter for breakdown and the secondary windings of transformers for an open circuit.
Sometimes it is necessary to disable the inverter protection for diagnostic purposes. In such cases, special care must be taken during work, and the protective circuits must be restored immediately after the repair is completed.
- 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 TNP0EA009 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 - cpu: VCT69 ***, EEPROM: 24C32 HDMI: SII9023. Defective components must be replaced.
In cases where there is no tuning to terrestrial or cable TV channels, you should make sure that the software is correct, as well as that the supply voltages on the TXN / B10AGNE tuner outputs are in accordance with the ratings. It is also necessary to check with an oscilloscope the presence of pulses of data exchange between the tuner and the processor via the I2C bus.
Owners of the TX-R26LE7 TV are advised to contact only qualified specialists with the necessary experience for repair! Attempts to repair yourself without the appropriate knowledge and skills can lead to irreversible negative consequences!

 There is an option TX-R32LE7K, TX-R32LE7KHA - Panel: LTA320WT-L06, Main: TNP0EA009 A 7, Power: TNP0EP009 P 9, Inverter: SSI320B12 Rev0.6.
 
DOWNLOAD SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>   Chassis  GLP21M for models TX-32LE7F, TX-32LE7L, TX-32LE7P (TX-32LE7K), TX-26LE7F, TX-26LE7L, TX-26LE7P (TX-26LE7K?) 



DOWNLOAD SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    TNP0EP009 Power supply


The appearance of the MainBoard TNP0EA009 is shown in the figure below:
TNP0EA009
External view of the power supply
The main features of the PANASONIC TX-R26LE7 device:
Installed matrix (LCD panel) LTA260W2-L12.
Matrix control uses a Timing Controller (T-CON) 260W2P4LV0.2.
The inverter INVUT260A is used to power the backlight lamps, it is controlled by the PWM controller BD9883AF.
The formation of the necessary supply voltages for all nodes of the PANASONIC TX-R26LE7 TV is carried out by the TNP0EP009 power module, or its analogs using MR4040 microcircuits and integrated power switches.
MainBoard - the main board (motherboard) is a TNP0EA009 module using cpu: VCT69 *** chips, EEPROM: 24C32 HDMI: SII9023 and others.
Tuner TXN / B10AGNE provides reception of TV programs and tuning to channels.
Additional technical information about the panel:
Brand: SAMSUNG
Model: LTA260W2-L12
Type: a-Si TFT-LCD, Panel
Diagonal size: 26.0 inch
Resolution: 1366x768, WXGA
Display Mode: Normally Black, Transmissive
Active Area: 575.769x323.712 mm
Display Colors: 16.7M (8-bit)
Frequency: 60Hz
Lamp Type: CCFL
PANASONIC TX-26LE7 TV with LCD display LTA260W2-L12, 26 "(66 cm) 16: 9 format diagonal. Screen brightness of 500 cd / m² provided by CCFL (EEFL) fluorescent lamps. Contrast as the ratio of maximum brightness to the minimum is 1000: 1.
The LTA260W2-L12 panel and TNP0EA009 firmware enable HD viewing at 1366x768 resolution for 720p graphics resolution (HD Ready). 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.
Speaker power 16 W (2x8 W) is provided by two 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, audio x2, S-Video, component, SCART x2, RGB, HDMI. 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: 640x480, 800x600, 1024x768, 1360x768.
Dimensions: with stand 657x525x239 mm, without stand 657x473x107 mm.
TV weight: without stand: 12.5 kg.
Attention! The LTA260W2-L12 panel of the PANASONIC TX-26LE7 LCD TV is a rather expensive component.

Avoid impacts on glass and pressure on the surface of the screen to avoid irreversible damage to the LCD panel!