Technical description and composition of the THOMSON 46M71NH20 TV, panel type and modules used. The composition of the modules.THOMSON
Model: 46M71NH20
Chassis / Version: MA1
Panel: LTA460WT-L14 ULB801196A
T-CON: 4046HDCP2LV0.6
Inverter (backlight): SSI46022S-H
Power Supply (PSU): 40-1PL46C-PWC1XG
PWM Power: NCP1027
MainBoard: ULB801196A V8-046SSAT LF1V650U8
IC MainBoard: MT8293AE, PS301A
Tuner: TEDE9-2C2B
Specifications 46M71NH20
THOMSON 46M71NH20
General recommendations for TV LCD repair
Possible malfunctions
- THOMSON 46M71NH20 TV does not turn on at all. No response to the remote control and front panel control buttons. Indicator lamps do not light up or flash.
In some of these cases, the main switching power supply, module 40-1PL46C-PWC1XG, 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 breakdowns in the secondary circuits of the converter, it can usually work in an emergency mode in a short-circuit mode, and with a short circuit in the power elements of the primary circuit, the mains fuse or current sensor in the source of the key most often breaks off.
The breakdown of power switches (MosFet) in switching sources is sometimes caused by malfunctions of other circuit elements, for example, in the circuits supplying the PWM controller, frequency setting or damper, as well as in the circuits of Negative Feedback (OOS) stabilization. PWM controllers (PWM) NCP1027, if they have no visible damage to the case and an outright short circuit between the pins, are usually checked by replacing.
- There is no picture, but there is sound, it reacts to the remote control. Or the image appears when turned on and immediately disappears
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. 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.
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 turn on, the indicator signals the standby or operating mode, or blinks.
Repair or diagnostics of the ULB801196A 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).
If you suspect a malfunction of the TEDE9-2C2B tuner, first of all, you need to make sure that the software is correct, as well as the presence of the necessary levels of supply voltages and pulses of data exchange with the processor via the I2C bus on the corresponding terminals of the tuner.
The lack of an image in the presence of a signal from THOMSON 46M71NH20 is often caused by a malfunction of the display backlight. Moreover, the problem can be both inside the LCD panel (matrix) LTA460WT-L14 ULB801196A, 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 LTA460WT-L14 LCD panel - a painstaking process that requires special attention and accuracy from the craftsman. In such cases, it is possible, with the slightest carelessness, 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 ULB801196A 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 the normal range, then the oscilloscope must track the passage of LVDS signals from the MainBoard ULB801196A, as well as synchronizing signals from T-CON to loops with drivers.
Attention to users! Self-repair of the THOMSON 46M71NH20 TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!
Additional MainBoard RepairThe appearance of the MainBoard ULB801196A is shown in the figure below:
ULB801196A
External view of the power supply
The main features of the THOMSON 46M71NH20 device:
Installed matrix (LCD panel) LTA460WT-L14 ULB801196A.
Matrix control uses Timing Controller (T-CON) 4046HDCP2LV0.6.
The inverter SSI46022S-H is used to power the backlight lamps.
The formation of the necessary supply voltages for all nodes of the THOMSON 46M71NH20 TV is carried out by the 40-1PL46C-PWC1XG power module, or its analogs using NCP1027 microcircuits.
MainBoard - the main board (motherboard) is a ULB801196A module, using MT8293AE, PS301A and others.
The TEDE9-2C2B tuner provides reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: SAMSUNG
Model: LTA460WT-L14
Type: a-Si TFT-LCD, Panel
Diagonal size: 46 inch
Resolution: 1366x768, WXGA
Display Mode: S-PVA, Normally Black, Transmissive
Active Area: 1018.35x572.544 mm
Surface: Antiglare (Haze 44%), Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 1800: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 10/6 (Tr / Td); 8 (G to G)
Frequency: 60Hz
Lamp Type: 22 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V
THOMSON 46M71NH20 LCD TV with LTA460WT-L14 LCD, 46 "(117 cm) diagonal, 16: 9 format. 550 cd / m² screen brightness is provided by CCFL (EEFL) lamps. Contrast - the ratio of maximum to minimum brightness is not less than 2000: 1 Dynamic contrast ratio of 5000: 1 is achieved by special control of the backlight operation depending on the brightness of the scene.It is possible to view in high quality HD at a resolution of pixels in 720p (HD Ready) .Input high-frequency or video signal is decoded in analog systems PAL, SECAM, NTSC Digital signal shaping (graphic format) is performed in the 480i, 480p, 576i, 576p, 720p, 1080i standards.
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 x3, S-Video, 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.
TV weight: 31 kg.
Attention! The LTA460WT-L14 ULB801196A panel of the THOMSON 46M71NH20 LCD TV is the most expensive component.
Avoid hitting the glass and putting pressure on the screen surface to avoid irreversible damage to the LCD panel!
