Technical description and composition of the PANASONIC TX-20LA80 TV, panel type and modules used. The composition of the modules.PANASONIC
Model: TX-20LA80
Chassis / Version: GLP21L
Panel: L5EDD5L00011 640 x 480
Lamp backlight: 6 Lamp CCFL
Inverter (backlight): STR-H2003
PWM Inverter: TPC8022-H
MOSFET Inverter: MR4030-7102
Trans Inverter: ETJV15ZF21AC
Power Supply (PSU): TNP0EP008
PWM Power: MR4030-710 (PWM + MOSFET)
MainBoard: TNP0EA008
IC MainBoard: CPU: VCT6753G
Tuner: ENGF7701GF
Control: Remote: EUR765101C, IR: TNP0EV008
TX-20LA80 Specifications
PANASONIC TX-20LA80
General recommendations for TV LCD repair
Possible malfunctions
- The PANASONIC TX-20LA80 TV does not turn on, does not respond to the remote control and control panel buttons, the indicators do not light up or flash.
Most often, with similar manifestations, the main power supply module TNP0EP008 turns out to be faulty. It is necessary to measure the output voltages in its secondary circuits, and in the event of their complete absence, the serviceability of the power switches and rectifier diodes should be checked for a possible breakdown (short circuit).
In case of breakdowns in the secondary circuits, the converter, as a rule, can operate in an emergency mode in a short circuit mode, and in case of a short circuit in the power elements of the primary circuit, the mains fuse usually breaks.
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. PWM microcircuits (PWM) MR4030-710 (PWM + MOSFET) are usually checked by replacing them with new ones, or knowingly working.
- There is no picture, but there is sound, it reacts to the remote control. Or the image appears when turned on and disappears immediately
These manifestations can be provoked by the power module, or by defects in the inverter, as well as by the skew of currents in the lamps due to their uneven wear. If all the electrolytic capacitors of the filter for the power supply of the inverter are in good working order, you should make sure that the lamps are in good condition, then you need to check the keys of the converter and the secondary windings of the transformers.
Sometimes, for diagnostic purposes, it is necessary to disable the inverter protection. In such cases, special care must be taken during work, and the protective circuits must be restored immediately after the repair is completed.
- The TV does not go into operation, does not respond to the remote control. The indicator on the front panel is on or blinking.
Repair or diagnostics of the TNP0EA008 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). Often the MB (SSB) board must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - CPU: VCT6753G and replace the failed chips with new ones. Some malfunctions may be associated with the use of BGA soldering technologies in modern Main Board. Usually such defects are detected by local heating of the chip.
A malfunction of the ENGF7701GF tuner is established after checking the software and all supply voltages at its terminals. 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-20LA80 TV without the appropriate qualifications and the necessary experience can lead to serious negative consequences!
DOWNLOAD SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> PANASONIC TX-20LA80 Chassis GLP21L for TX-20LA80F, TX-20LA80FS.
The appearance of the MainBoard TNP0EA008 is shown in the figure below:TNP0EA008
External view of the power supply
The main features of the PANASONIC TX-20LA80 device:
Installed matrix (LCD-panel) L5EDD5L00011 640 x 480.
To power the backlight lamps, an STR-H2003 inverter is used, controlled by the TPC8022-H PWM controller. The transformer ETJV15ZF21AC is installed in the inverter converter. Keys of type MR4030-7102 are used as power elements of the inverter.
The formation of the necessary supply voltages for all nodes of the PANASONIC TX-20LA80 TV is carried out by the TNP0EP008 power module, or its analogs using MR4030-710 microcircuits (PWM + MOSFET).
MainBoard - the main board (motherboard) is a TNP0EA008 module, using CPU chips: VCT6753G and others.
The ENGF7701GF tuner provides reception of television programs and tuning to channels.
PANASONIC TX-20LA80 TV with LCD display L5EDD5L00011, 20 "diagonal 4: 3 format. Screen brightness 450 cd / m² provided by CCFL (EEFL) fluorescent lamps. Dynamic contrast ratio 8000: 1 is provided by special control of backlight operation depending on illumination of areas in the scene.An input analog video signal can be processed in PAL, SECAM, NTSC.Graphic processing and image formation of a digital signal occurs in the standards 480i, 480p, 576i, 576p, 720p.
The power of the acoustic audio system is 6 W (2x3 W) provided by two speakers. NICAM STEREO sound processing system is used.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, S-Video, component, SCART x2, RGB. A headphone output is provided for individual listening.
The power consumed by the TV in operating mode from the network is 52 W.
Dimensions: with stand 498x484x233 mm, without stand 498x443x98 mm.
TV weight: 7.5 kg.
Attention! Panel L5EDD5L00011 640 x 480 LCD TV PANASONIC TX-20LA80 is quite an expensive component.
Avoid impacts on glass and pressure on the surface of the screen to avoid irreversible damage to the LCD panel!