Wednesday, 7 April 2021

REPAIRING / SERVICING TV THOMSON T24D16DH-02B

 Technical description and composition of THOMSON T24D16DH-02B TV, type of panel and modules used. Module composition.
Composition
Specifications
THOMSON T24D16DH-02B
LCD TV LED T24D16DH-02B | Year of manufacture: 2017
Screen diagonal: 24" (61 cm)
Screen Format: 16:9
Resolution: 1366x768
Refresh rate:     50Hz
LED backlight: Yes, Direct LED
Support HD: 720p HD
Brightness: 180 cd/m2
Contrast: 3000:1
Viewing Angle: 176°
Pixel Response Time:     6.5 ms
Progressive scan: Yes
Digital tuner: DVB-T, DVB-T2, DVB-C
Number of channels: 799
Teletext: there is
Multimedia: MP3, MPEG4, HEVC (H.265), Xvid, MKV, JPEG
Sound stereo: there is
Sound power: 6W (2x3W)
Acoustics: two speakers
Interface: VGA, HDMI, USB
Headphone jack: yes
TV weight: 2.65 kg
Dimensions: with stand 553x380x134 mm
without stand 553x332x82 mm
Find out more...
THOMSON T24D16DH-02B

THOMSON LED
Model: T24D16DH-02B

Chassis/Version: TP.MS3463S.PA583

Panel: LVW240CMDX E5 V12

LED backlight: 3030 6V

LED driver (backlight): integrated into MainBoard

PWM LED driver: MP3398A

MOSFET LED driver: TO-252

Power Supply (PSU): integrated into MainBoard

PWM Power: PWM SOT23-6

MOSFET Power: TO-252

MainBoard: TP.MS3463S.PA583

IC MainBoard: SPI FLASH: GD25Q64

TP: CDT-9NT372-RF01
General advice about LCD LED TV repair
Possible trouble spots

- THOMSON T24D16DH-02B TV set does not turn on, does not respond to the remote control and control panel buttons, does not shine or blink indicators.

In these cases the AC/DC converter which is integrated to the main board TP.MS3463S.PA583 is often at fault. You should measure its output voltages, and if they are not, check the condition of the power switches (TO-252) of the converters and the rectifier diodes for possible short circuits.
If there is a breakdown in the secondary circuits of the inverter, it can usually fail in the short-circuit mode, and a short in the power elements of the primary circuit most often breaks the mains fuse or current sensor in the source of the key.
Breakdown of power switches (MosFet) in pulse sources, sometimes caused by faults in other circuit elements, for example, in the circuits that feed the PWM controller, frequency-retaining or damping circuits, as well as in the negative feedback (negative feedback) stabilization circuits. PWM regulators (PWM) PWM SOT23-6, if they do not have visible case damage and outright short circuits between pins, are usually checked by replacement.

- No image, the screen is black, there is sound, with external screen illumination you can sometimes see faintly visible outlines of the image.

Usually in such cases there is no backlight of the LED panel (matrix). The reason for this may be a breakage in the circuit LED 3030 6V, or a problem in stabilizing their power.
To check the LED arrays for breakage without disassembling the panel you can, for example, use a power supply. It is not possible to open the series connected PN-junctions with a simple multimeter, you will need a voltage of about several tens of volts.

If the THOMSON T24D16DH-02B has no picture but has sound, often the LVW240CMDX E5 V12 display backlight is just not working. Moreover, in LED TVs usually fail LEDs inside the panel, less often the LED driver.
In such cases, you can see a barely noticeable image when external light hits the screen.

To replace the LEDs requires disassembly of the LCD panel LVW240CMDX - a process which requires a master of experience and skill. It is not recommended to perform such works by yourself to owners of TV sets and craftsmen who have no experience in LCD panel repair


READ HOW TO REPAIR THE TV LED BACKLIGHT --------------> HERE.


If there is no image, but the backlight works - the screen becomes slightly lighter when the TV is turned on, and in the open TV you can see the light through the holes in the body of the panel.
In this case the panel may be defective - damage to the strips, cables, for example, as a consequence of moisture after an unsuccessful washing of the screen, the T-CON board (Timing Controller) may be defective. But quite often the MainBoard TP.MS3463S.PA583 is defective, so software defects are also possible.
Then first it is necessary to check the panel power supply voltage, the fuses on the T-CON board, as well as the supply and reference voltages of the column and line drivers - VGH, VGL, Vcom.
If these measurements are within normal limits, you need to trace by oscilloscope the LVDS signals from MainBoard TP.MS3463S.PA583, as well as synchronizing signals to driver stubs.

Filled or badly washed LED TV screens can be repaired in about half of the cases, usually, if there is no significant damage in the cables and panel bars.


- The TV set doesn't go into the operating mode, the remote control doesn't respond. Front panel indicator glows constantly or blinks.

Repair or diagnostic of the TP.MS3463S.PA583 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 (firmware). Complex repair of MB board (SSB) in some cases is possible and practiced by repairers. To do this you should check and if necessary replace SPI FLASH elements: GD25Q64. BGA chips failures are usually easy to detect by heating method.

If there is no TV channel reception, but the TV set is working properly from external devices, first of all you should check the CDT-9NT372-RF01 tuner supply voltage and update the software. It is necessary to control the data exchange impulses via I2C bus with the help of oscilloscope.

Once again I remind users! The attempts to repair THOMSON T24D16DH-02B TV without proper qualification and necessary experience may result in its complete unrepairability!



After repair of TP.MS3463S.PA583, MP3398A backlight. Information from the master.

Decrease backlight current from 280 mA to 210 mA - I installed one 18 kOhm instead of two parallel connected 15 kOhm and 100 kOhm resistors on pin 6 of MP3398A ISET chip.

DOWNLOAD SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>   TP.MS3463.PA583 Power supply.  schematic.


Current limitation. TP.MS3463S.PA583, MP3398A. General advice.


To reduce the backlighting current in TV's with the TP.MS3463S.PA583 board and the MP3398A controller you should increase the total resistance of the resistors in proportion to the case on pin 6 of the MP3398A ISET controller.
The resistors in the diagram are labeled RB812, RB813, RB822.


Inverse proportion formula for backlight current in milliamps and resistance Rset in kiloohms:
I[mA]=988/Rset[kOhm].


TP.MS3463S.PA583 current backlight
A pdf document is included.--------------->  MP3398A.

Ways to limit the current in LED backlight drivers:

There is a lot of information on the Internet about ways to limit the current in the LED backlighting for different TVs and LED drivers. A lot of it is written plausibly but sometimes it is written by people far from electronics in order to publish any popular content on hot topics to boost web-sites ratings.

It's impossible to talk about each case separately within one article, because even similar models may have different panels and different boards with their own driver variants. But there are basic principles that are clear to craftsmen with even minimal knowledge and skill.


Other popular, complex and controversial current limit cases will be published as information becomes available.
There are three basic ways to reduce the backlight current.

1. By increasing the resistance of the LED current sensor - a low-resistance measuring resistor in the cathode (LED-) circuit.
2. Increasing the ratings of the resistors on the ISET (current setting) input of the LED driver chip.
3. changing the resistor ratings in the divider on the ADIM (Dimming) control input.

The fundamental difference between input ISET and ADIM is that ISET - input inverted, as FB, and ADIM - direct.


More on MainBoard repair

The MainBoard TP.MS3463S.PA583 is shown in the figure below:

TP.MS3463S.PA583

The main features of THOMSON T24D16DH-02B:

LVW240CMDX E5 V12 matrix (LED panel) is installed.
To power the LED backlight using a converter, combined with the main board TP.MS3463S.PA583, controlled by the PWM controller MP3398A. As power elements of the LED driver are used as TO-252-type switches.
The power module is combined with MainBoard and is designed as reverse-going AC/DC converter with PWM SOT23-6 chips and TO-252 type power switches.
MainBoard - the main board (motherboard) is a TP.MS3463S.PA583 module, using SPI FLASH: GD25Q64 and other microcircuits.
The CDT-9NT372-RF01 tuner provides TV program reception and channel tuning.


PWM SMPS in SOT-23-6, SOT-26, TSOP-6 packages

In the circuitry of modern switching power supplies (SMPS), PWM controllers made in small-sized planar packages with six terminals have gained wide popularity. The enclosure type designation can be SOT-23-6, SOT-23-6L, SOT-26, TSOP-6, SSOT-6. The appearance and arrangement of the pins are shown in the figure below. In this case, the code marking LD7530A is shown on the left fragment of the picture.


 

 Pin assignment:
1 - GND. (Common wire).
2 - FB. (FeedBack - Feedback). Input for controlling the duration of pulses with a signal from the output voltage. Sometimes it can be labeled COMP (input comparator).
3 - RI / RT / CT / COMP / NC - Depending on the type of microcircuit, it can be used for a frequency-setting RC circuit (RI / RT / CT), or for organizing protection, as an input of a PWM trip comparator at a threshold value at its input, specified in the document. In some types of microcircuits, this input may not be used in any way (NC - No Connect).
4 - SENSE, otherwise CS (Current Sense) - Input from the current sensor at the source of the key.
5 - VCC - Input voltage supply and start of the microcircuit.
6 - OUT (GATE) - Output for controlling the gate (Gate) of the key.

Functionally, these regulators work on the principle of the previously popular xx384x PWM microcircuits, which have proven themselves well in terms of reliability and stability.

Some difficulties often arise when replacing or choosing an analog for such PWM regulators due to the use of code markings in the designation of the type of microcircuits. The situation is complicated by a large number of component manufacturers who do not always provide documentation to the mass access, just as not all manufacturers of finished devices supply repair service centers with diagrams, so repairmen often have to study real circuit solutions by installed components and wiring connections directly on the board.

In practice, PWM microcircuits and the marking code EAxxx and Eaxxx are often found. Official documentation for them was not found in the public domain, but discussions on the forums and pieces of pictures from PDF from System General, which publishes them as SG6848T and SG6848T2, have survived. The drawing is here placed left .


 

For the attention of the masters, here below are PDF datasheet tables compiled from information available on the Internet and PDF documents for the selection of analogues types when replacing the most common six-legged planar PWM with pinout pins: pin1 - GND, pin2 - FB (COMP), pin4 - Sense, pin5 - Vcc, pin6 - OUT ...
Their main difference is the application and purpose of pin 3. 

 

NamePart NumberFabricantMarking
SG6849SG684965TZFairchild / ON SemiBBxx
SG6849SG6849-65T, SG6849-65TZSystem GeneralMBxx EBxx
SGP400SGP400TZ System General AAKxx

 

 PWM controllers (PWM) with a 95-100 kOhm resistor on pin 3.

When applying the PWM listed below, the frequency should be set with the RT (RI) resistor from pin 3 to ground. Usually its nominal value is chosen 95-100 kOhm for a frequency of 65-100 KHz. For more details, see the here below attached documentation. PDF files are packed in RAR.

 

NamePart NumberFabricantMarking
AP3103AAP3103AKTR-G1Diodes IncorporatedGHL
AP8263AP8263E6R, A8263E6VRAiT SemiconductorS1xx
AT3263AT3263S6ATC Technology3263
CR6848CR6848SChip-Rail848H16
CR6850CR6850SChip-Rail850xx
CR6851CR6851SChip-Rail851xx
FAN6602RFAN6602RM6XFairchild / ON SemiACCxx
FS6830FS6830FirstSemi
GR8830GR8830CGGrenergy30xx
GR8836GR8836C, GR8836CGGrenergy36xx
H6849H6849NFHI-SINCERITY
H6850H6850NFHI-SINCERITY
HT2263HT2263MPHOT-CHIP63xxx
KP201
Kiwi Instruments
LD5530LD5530GL LD5530RLeadtrandxxt30 xxt30R
LD7531LD7531GL, LD7531PLLeadtrendxxP31
LD7531ALD7531AGLLeadtrendxxP31A
LD7535/ALD7535BL, LD7535GL, LD7535ABL, LD7535AGLLeadtrendxxP35-xxx35A
LD7550LD7550BL, LD7550ILLeadtrendxxP50
LD7550BLD7550BBL, LD7550BILLeadtrend xxP50B
LD7551LD7551BL/ILLeadtrendxxP51
LD7551CLD7551CGLLeadtrendxxP51C
NX1049XN1049TPXian-Innuovo49xxx
OB2262OB2262MPOn-Bright-Electronics62xx
OB2263OB2263MPOn-Bright-Electronics63xx
PT4201PT4201E23FPowtech4201
R7731R7731GE/PERichtek0Q=
R7731AR7731AGERichtekIDP=xx
SD4870SD4870TRSilan Microelectronics4870
SF1530SF1530LGTSiFirst30xxx
SG5701SG5701TZSystem GeneralAAExx
SG6848SG6848T, SG6848T1, SG6848TZ1, SG6848T2Fairchild / ON SemiAAHxx EAxxx
SG6858SG6858TZFairchild / ON SemiAAIxx
SG6859ASG6859ATZ, SG6859ATYFairchild / ON SemiAAJFxx
SG6859SG6859TZFairchild / ON SemiAAJMxx
SG6860SG6860TYFairchildAAQxx
SP6850SP6850S26RGSporton Lab850xx
SP6853SP6853S26RGB, SP6853S26RGSporton Lab853xx
SW2263SW2263MPSamWin
UC3863/GUC3863G-AG6-RUnisonic Technologies CoU863 U863G
XN1049XN1049, XN1049TPInnuovo Microelectronics49 xxx

 

 PWM controllers that use pin 3 differently.

When using the following PWM (PWM controllers), you should pay attention to pin 3, which can be used to organize protection - thermal or from overvoltage of the input voltage.
The frequency can be fixed at 65kHz, or set by the value of the capacitor at pin 3.
When replacing any microcircuits with analogs, carefully study the documentation. PDF files are packed in a RAR archive.

 

NamePart NumberFabricantMarking
AP3105/V/L/RAP3105KTR-G1, AP3105VKTR-G1, AP3105LKTR-G1, AP3105RKTR-G1Diodes IncorporatedGHN GHO GHP GHQ
AP3105NA/NV/NL/NRAP3105NAKTR-G1, AP3105NVKTR-G1, AP3105NLKTR-G1, AP3105NRKTR-G1Diodes IncorporatedGKN GKO GKP GKQ
AP3125A/V/L/RAP3125AKTR-G1, AP3125VKTR-G1, AP3125LKTR-G1, AP3125RKTR-G1Diodes IncorporatedGLS GLU GNB GNC
AP3125BAP3125BKTR-G1Diodes IncorporatedGLV
AP3125HA/HBAP3125HAKTR-G1, AP3125HBKTR-G1Diodes IncorporatedGNP GNQ
AP31261AP31261KTR-G1Diodes IncorporatedGPE
AP3127/HAP3127KTR-G1, AP3127HKTR-G1Diodes IncorporatedGPH GSH
AP3301AP3301K6TR-G1Diodes IncorporatedGTC
FAN6862FAN6862TYFairchild / ON SemiABDxx
FAN6863FAN6863TY, FAN6863LTY, FAN6863RTYFairchild / ON SemiABRxx
HT2273HT2273TPHOT-CHIP73xxx
LD7510/JLD7510GL, LD7510JGLLeadtrendxxP10 xxP10J
LD7530/ALD7530PL, LD7530GL, LD7530APL, LD7530AGLLeadtrendxxP30 xxxP30A
LD7532LD7532GLLeadtrendxxP32
LD7532ALD7532AGLLeadtrendxxP32A
LD7532HLD7532HGLLeadtrendxxP32H
LD7533LD7533GLLeadtrendxxP33
LD7536LD7536GLLeadtrendxxP36
LD7536RLD7536RGLLeadtrendxxP36R
LD7537RLD7537RGLLeadtrendxxP37R
LD7539C GLLD7539C GLLeadtrendxxP39C
ME8204ME8204M6GMicrOneME8204xx
NCP1250NCP1250ASN65T1G, NCP1250BSN65T1G, NCP1250ASN100T1G, NCP1250BSN100T1GON Semiconductor25xxxx
NCP1251NCP1251ASN65T1G, NCP1251BSN65T1G, NCP1251ASN100T1G, NCP1251BSN100T1GON Semiconductor5xxxxx
OB2273OB2273MPOn-Bright-Electronics73xx
R7735R7735AGE, R7735HGE, R7735GGE, R7735RGE, R7735LGERichtek
UC3873/GUC3873-AG6-R, UC3873G-AG6-RUnisonic TechnologiesU873 U873G
 



THOMSON T24D16DH-02B LED TV with LVW240CMDX LCD screen measuring 24" (61 cm) diagonally in 16:9 aspect ratio. Claimed 180 cd/m² brightness is provided by an advanced LED backlight and has a maximum brightness to minimum contrast ratio of at least 3000:1. The LCD panel uses direct backlighting with Direct LED backlighting.
LVW240CMDX matrix and MainBoard software TP.MS3463S.PA583 realize HD image quality with 1366x768 pixels resolution in 720p (HD Ready) graphic resolution. Supports multimedia formats: MP3, MPEG4, HEVC (H.265), Xvid, MKV, JPEG.
The speaker system has 6W (2x3W) sound power provided by two speakers. NICAM STEREO audio processing system is used.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), VGA, HDMI, USB. There is a jack for headphones. The digital tuner receives DVB-T, DVB-T2, DVB-C TV channels.

The power supply is used as a part of MainBoard.

Dimensions: with stand 553x380x134 mm, without stand 553x332x82 mm.

TV weight: 2.65kg.

Warning. The LVW240CMDX E5 V12 LED TV THOMSON T24D16DH-02B is an expensive and fragile part of the TV.
Avoid any kind of impact on the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also not safe to get liquid on the screen. Sometimes one drop is enough if it drips down the glass onto the cables and the TV becomes unrepairable.