Technical description and composition of the THOMSON 40M71NH20 TV, panel type and modules used. The composition of the modules.THOMSON
Model: 40M71NH20
Chassis / Version: MT01
Panel: LTA400WT-L17
T-CON: 4046HDCP2LV0.6
Inverter (backlight): SSI400WA16
Power Supply (PSU): JSK4338-007A (81-LC40B6-PW1)
PWM Power: L6563 (PFC 14pin), ICE3B0565, L6599D
MainBoard: 40-MT01TI-MAC2XG
IC MainBoard: MT8201AE S29AL016M 24C32MN, K4S641632K
Tuner: TEDE9-2C2B
Control: IR: 40-32M61N-IRD1XG
Specifications 40M71NH20
THOMSON 40M71NH20
General recommendations for TV LCD repair
Possible manifestations of malfunctions
- The THOMSON 40M71NH20 TV does not turn on and does not show any signs of turning on, does not respond to the control buttons and the remote control.
In such cases, the fault should be looked for primarily in the power module. Its output voltages should be measured, and if they are absent, check the serviceability of the power switches of the converters and rectifier diodes for the probability of a short circuit.
In the event of diode breakdowns in the secondary circuits, the converter can operate in an emergency mode of short circuit without output voltages, and in the event of a short circuit in the power elements of the primary circuit, the mains fuse and / or the current sensor in the source of the key 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 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 the transformers for an open circuit.
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, does not respond to the remote control. The indicator blinks or signals the standby mode.
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 - EEPROM 24C32WP, percent: MT8201AE.flash S29AL016D and replace the failed chips with new ones. Some malfunctions can be associated with the use of BGA soldering technologies in modern Main Board. Usually such defects are detected by local heating of the chip.
Before changing the TEDE9-2C2B - TDA9886T.МТ8293AE tuner, if there is no possibility of tuning to television channels, you should make sure that there are supply voltages, which must be measured at the corresponding tuner terminals and check the software for correctness. The pulses of the data exchange of the tuner with the processor can be monitored with an oscilloscope.
The lack of an image in the presence of a signal from THOMSON 40M71NH20 is often caused by a malfunction of the display backlight. Moreover, the problem can be both inside the LCD panel (matrix) LTA400WT-L17, 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, repairing the backlight requires disassembling the LTA400WT-L17 LCD panel - 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-MT01TI-MAC2XG 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 the above measurements are within the normal range, then the oscilloscope should track the passage of LVDS signals from MainBoard 40-MT01TI-MAC2XG, as well as synchronization signals from T-CON to loops with drivers.
We remind users again! Attempts to repair the THOMSON 40M71NH20 TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!
Additional MainBoard RepairThe appearance of MainBoard 40-MT01TI-MAC2XG is shown in the figure below:
40-MT01TI-MAC2XG
External view of the power supply
The main features of the THOMSON 40M71NH20 device:
Installed matrix (LCD panel) LTA400WT-L17.
Matrix control uses Timing Controller (T-CON) 4046HDCP2LV0.6.
An SSI400WA16 inverter is used to power the backlight lamps.
The formation of the necessary supply voltages for all nodes of the THOMSON 40M71NH20 TV is carried out by the JSK4338-007A power module, or its analogs using L6563 (PFC 14pin), ICE3B0565, L6599D microcircuits.
MainBoard - the main board (motherboard) is a 40-MT01TI-MAC2XG module, using MT8201AE S29AL016M 24C32MN, K4S641632K and others.
The TEDE9-2C2B tuner provides reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: SAMSUNG
Model: LTA400WT-L17
Type: a-Si TFT-LCD, Panel
Diagonal size: 40 inch
Resolution: 1366x768, WXGA
Display Mode: S-PVA, Normally Black, Transmissive
Active Area: 885.168x497.664 mm
Surface: Antiglare (Haze 44%), Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 2000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 10/6 (Tr / Td); 8 (G to G)
Frequency: 60Hz
Lamp Type: 16 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V
LCD TV THOMSON 40M71NH20 with LCD, diagonal 40 "(102 cm) format 16: 9. Screen brightness 550 cd / m² provided by CCFL (EEFL) lamps. Dynamic contrast ratio 5000: 1 is achieved by special control of the backlight depending on on the brightness of the scene.It is possible to view in high quality HD at a resolution of 1366x768 pixels in the standard 720p (HD Ready) .Input high-frequency or video signal is decoded in analog systems PAL, SECAM, NTSC. Digital signal formation (graphic format) is performed in the standards 480i, 480p, 576i, 576p, 720p.
Speaker power 30 W (2x15 W) is provided by two speakers. The NICAM STEREO audio processing system is used.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x3, SCART x2, RGB. 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.
TV weight: 29 kg.
Attention! The THOMSON 40M71NH20 LCD TV panel is the most expensive component.
Avoid hitting the glass and putting pressure on the screen surface to avoid irreversible damage to the LCD panel!
