Technical description and composition of the THOMSON 20A08F50 TV, panel type and modules used. The composition of the modules.THOMSON
Model: 20A08F50
Chassis / Version: GM21
Panel: A201SN02 V.5
T-CON: HT201V01-100-X0.3 (Sticker: BMAA50420 0162) SPFD3501A-HL092 NT7181FG TPS65140 5411IREZ
Inverter (backlight): 08-IN2011-PWY 40-0LCD20-IVC1XG
PWM Inverter: OZ9925GN (16)
MOSFET Inverter: 45P03 (3), T40N03G (3), 50N03-10
Trans Inverter: MK BK-12-708 BY
Power Supply (PSU): BCK-3239A
MainBoard: 40-LDM21B-DIE4XG LCD20GM21A08
IC MainBoard: A7551C, TVP5147, KIA278, 4576
Tuner: TCL08121951E 07-389F15-NAN4G
Specifications 20A08F50
THOMSON 20A08F50
General recommendations for TV LCD repair
Possible malfunctions
- The THOMSON 20A08F50 TV does not turn on and does not show any signs of operability at all. No response to the remote control and front panel control buttons.
With similar manifestations, in some cases, the BCK-3239A power supply module is faulty. It is then necessary to measure its output voltages and, in their absence, the power switches and rectifier diodes of the converters should be checked for the probability of a short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in short-circuit mode, and in case of short-circuit in the elements of the primary circuit, the mains fuse usually breaks off.
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, in the absence of visible damage or outright short circuits between the terminals, are checked by replacing them with new ones, or knowingly working properly.
- 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.
These manifestations can be triggered by the power module, or by defects in the inverter, as well as by skewed 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.
If, when diagnosing a malfunction, it is required to turn off the inverter protection, there is a risk of failure of the power elements of the inverter, and special care is required during work, and after they are completed, it is imperative to restore the protection circuits for the further safe operation of the TV by the owner in normal mode.
- The TV does not turn on, the indicator signals the standby or operating mode, or blinks.
Repair or diagnostics of the 40-LDM21B-DIE4XG motherboard should begin with checking the stabilizers and power converters required to power the microcircuits and matrix. If necessary, you should update or replace the software (software). In cases of attempts to repair the MB (SSB) board, it is necessary to check the serviceability of its elements - A7551C, TVP5147, KIA278, 4576, which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its pins with the board (indicated by warming up).
If the TV operates normally from external devices, but does not tune to TV channels, the TCL08121951E 07-389F15-NAN4G tuner may be faulty. In such cases, first of all, you should make sure that there are supply voltages at its corresponding terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the reason for the inoperability of the tuner may be a software failure.
The lack of an image in the presence of a signal from THOMSON 20A08F50 is often caused by a malfunction of the display backlight. Moreover, the problem can be both inside the LCD panel (matrix) A201SN02 V.5, for example, a malfunction of CCFL (EEFL) lamps, and outside in their power source - an inverter.
Without backlighting, sometimes you can see a barely noticeable image with a certain successful hit of external light on the screen.
Often, to repair the backlight, disassembly of the A201SN02 LCD panel is required - a painstaking process that requires special attention and accuracy from the master. In such cases, there is a possibility, with the slightest negligence, to damage the glass or loops and the TV may become unrepairable.
We strongly do not recommend doing such work to owners of TVs and craftsmen who do not have experience in repairing LCD panels! Moreover, at home (at the owner's home).
If there is no image in the presence of backlight, the screen becomes slightly lighter when turned on, and if the TV is open, the light from the lamps can be seen through the holes in the panel case.
In this case, there may be a malfunction inside the panel, damage to strips, loops, the T-CON board (Timing Controller) may be defective. But the main board MainBoard 40-LDM21B-DIE4XG often turns out to be faulty; a software failure is also possible.
In such cases, the master first of all needs to check the main supply voltage of the panel at the LVDS connector, the fuses on the T-CON board or the panel brackets, as well as the supply and reference voltages for line and column drivers - VGH, VGL, Vcom.
If all of the above measurements are within normal limits, then the oscilloscope should track the passage of LVDS signals from MainBoard 40-LDM21B-DIE4XG, as well as synchronizing signals from T-CON to loops with drivers.
We remind users again! Attempts to self-repair a THOMSON 20A08F50 TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!
The appearance of the MainBoard 40-LDM21B-DIE4XG is shown in the figure below:
40-LDM21B-DIE4XG
40-LDM21B-DIE4XG can be used in TVs:
THOMSON 15A08F50 (Panel HT150X02-100), THOMSON 20A08F50 (Panel A201SN02 V.5).
External view of the power supply
The main features of the THOMSON 20A08F50 device:
Installed matrix (LCD-panel) A201SN02 V.5.
Matrix control uses Timing Controller (T-CON) HT201V01-100-X0.3.
To power the backlight lamps, the 08-IN2011-PWY inverter is used, controlled by the OZ9925GN PWM controller (16). The transformer MK BK-12-708 BY is installed in the inverter converter. Keys of type 45P03 (3), T40N03G (3), 50N03-10 are used as power elements of the inverter.
The formation of the necessary supply voltages for all nodes of the THOMSON 20A08F50 TV is carried out by the BCK-3239A power module, or its analogues.
MainBoard - the main board (motherboard) is a 40-LDM21B-DIE4XG module, using A7551C, TVP5147, KIA278, 4576 and others.
Tuner TCL08121951E 07-389F15-NAN4G provides reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: AUO
Model: A201SN02 V5
Type: a-Si TFT-LCD, Panel
Diagonal size: 20.1 inch
Resolution: 800x600, SVGA
Display Mode: TN, Normally White, Transmissive
Active Area: 408x306 mm
Surface: Antiglare
Brightness: 450 cd / m²
Contrast Ratio: 700: 1
Display Colors: 16.2M (6-bit + FRC), CIE1931 72%
Response Time: 11/5 (Tr / Td)
Frequency: 60Hz
Lamp Type: 6 pcs CCFL Without Driver
Signal Interface: TTL (1 ch, 8-bit), 50 pins
Voltage: 5.0V
LCD TV THOMSON 20A08F50 with LCD A201SN02, 20 "diagonal in 4: 3 format. Screen brightness of 500 cd / m² is provided by CCFL (EEFL) lamps. Contrast - the ratio of maximum to minimum brightness is at least 700: 1. Input high-frequency or video signal is decoded in analog systems PAL, SECAM, NTSC Digital signal formation (graphic format) is performed in 480i, 480p, 576i, 576p standards.
Speaker power 10 W (2x5 W) is provided by two speakers. Uses the NICAM stereo signal processing system and the Sound Surround function.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV x2, audio x2, S-Video, component, VGA. A headphone jack is provided. A standard VGA (D-Sub 15) connector is used to connect a laptop or computer. This interface supports resolutions: 640x480, 800x600, 1024x768.
Attention! The A201SN02 V.5 panel of the THOMSON 20A08F50 LCD TV is its most expensive component.
Avoid hitting the glass and putting pressure on the screen surface to avoid irreversible damage to the LCD panel!
