Wednesday 9 September 2020

REPAIRING / SERVICING TV THOMSON 46FE9234B

Technical description and composition of the THOMSON 46FE9234B TV, panel type and modules used. The composition of the modules.
THOMSON
Model: 46FE9234B
Panel: LTA460HA07
T-CON: FHD60C4LV1.0, MAX9591, TPS65167A, THF9301
Inverter (backlight): SSI460-16A01
PWM Inverter: OZ9972SN
MOSFET Inverter: MDD1752 x8
Power Supply (PSU): 40-PWL46C-PWH1XG
PWM Power: NCP1653A, NCP1014AP06, LM339
MOSFET Power: 17A06, 2SK3568, TK13A60D
MainBoard: 40-MT5362-MAB4XG
IC MainBoard: MT8295AE, TDA9886T, TDA1308, 24C16WP
Tuner: TDQG8-601A
Control: RC1994925
Specifications 46FE9234B
THOMSON 46FE9234B
General recommendations for TV LCD repair
Possible malfunctions
- TV THOMSON 46FE9234B does not turn on, does not respond to the remote control and control panel buttons, does not light or blink indicators.
Often in such cases, the 40-PWL46C-PWH1XG power supply module is faulty. It is necessary to measure its output voltages, and if they are absent (full or partial), check the serviceability of the power switches (17A06, 2SK3568, TK13A60D) of the converters and rectifier diodes for a possible short circuit.
In case of any breakdowns in the secondary circuits, the converter can operate in an emergency mode of a short circuit, and with a short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key often 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 NCP1653A, NCP1014AP06, LM339, in the absence of visible damage or outright short circuits between the terminals, are checked by replacing them with new ones, or known to be working properly.
- There is no picture, but there is sound and reaction to commands from the remote control. Or the image appears immediately after switching on and 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. 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 indicator on the front panel blinks, the TV does not turn on in operating mode, does not respond to the remote control.
Repair or diagnostics of the 40-MT5362-MAB4XG 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). Complicated repair of MB (SSB) board is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace elements MT8295AE, TDA9886T, TDA1308, 24C16WP. BGA chip faults are usually easy to detect by warm-up.
If you suspect a malfunction of the TDQG8-601A 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 tuner pins.

The lack of an image when there is a signal from THOMSON 46FE9234B is often caused by a malfunction of the display backlight. Moreover, the problem can be both inside the LCD panel (matrix) LTA460HA07, 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 LTA460HA07 LCD panel - a painstaking process that requires special attention and accuracy from the technician. 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-MT5362-MAB4XG 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-MT5362-MAB4XG, as well as synchronizing signals from T-CON to loops with drivers.
Owners of the 46FE9234B 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!

Additional MainBoard Repair
The appearance of the MainBoard 40-MT5362-MAB4XG is shown in the figure below:
40-MT5362-MAB4XG
40-MT5362-MAB4XG can be used in TVs:
TCL 26A33H (Panel T260XW02 V.P), THOMSON 46FE9234B (Panel LTA460HA07).
The main features of the THOMSON 46FE9234B device:
Installed matrix (LCD-panel) LTA460HA07.
Matrix control uses Timing Controller (T-CON) FHD60C4LV1.0.
To power the backlight lamps, the SSI460-16A01 inverter is used, controlled by the OZ9972SN PWM controller. The keys of the MDD1752 x8 type are used as power elements of the inverter.
The formation of the necessary supply voltages for all nodes of the THOMSON 46FE9234B TV is carried out by the 40-PWL46C-PWH1XG power module, or its analogs using NCP1653A, NCP1014AP06, LM339 microcircuits and power switches of the 17A06, 2SK3568, TK13A60D type.
MainBoard - the main board (motherboard) is a 40-MT5362-MAB4XG module, using the MT8295AE, TDA9886T, TDA1308, 24C16WP and others.
Tuner TDQG8-601A provides reception of television programs and tuning to channels.


Additional technical information about the panel:
Brand: SAMSUNG
Model: LTA460HA07-W02
Type: a-Si TFT-LCD, Panel
Diagonal size: 46 inch
Resolution: 1920x1080, FHD
Display Mode: S-PVA, Normally Black, Transmissive
Active Area: 1018.08x572.67 mm
Surface: Antiglare, Hard coating (7H)
Brightness: 450 cd / m²
Contrast Ratio: 4000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 8 (G to G)
Frequency: 60Hz
Lamp Type: 16 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V
THOMSON 46FE9234B LCD TV with LTA460HA07 LCD, 46 "(117 cm) diagonal 16: 9. Screen brightness of 500 cd / m² provided by CCFL (EEFL) backlight. Dynamic contrast ratio of 50,000: 1 achieved by special backlight control in depending on the brightness of the scene.The design and technical capabilities of the TV provide viewing in high quality HD at a resolution of 1920x1080 pixels in graphic decomposition according to the standard 1080p (Full HD) .Input high-frequency or video signal is decoded in analog systems PAL, SECAM, NTSC. Digital signal formation (graphic format) is produced in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p Multimedia formats are supported: MP3, MPEG4, JPEG.
Speaker power 16 W (2x8 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, audio x3, component, SCART x2, RGB, VGA, HDMI x2, USB. 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, 1360x768. The digital tuner has the ability to receive TV channels in DVB-T MPEG4 standards.
The power consumed by the TV from the network in the operating mode is not more than 230 W.
Dimensions: with stand 1130x792x285 mm, without stand 1130x726x112 mm.
TV weight: with stand: 28.8 kg, without stand: 25 kg.
Attention! The LTA460HA07 panel of the THOMSON 46FE9234B 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!