Technical description and composition of the TELEFUNKEN TF-LED32S74T2 TV, type of panel and modules used. Module composition.
Composition Specifications
TELEFUNKEN TF-LED32S74T2
LCD TV LED TF-LED32S74T2 | Year of manufacture: 2018
Screen diagonal: 31.5" (80 cm)
Screen Format: 16:9
Resolution: 1366x768
Refresh rate: 50Hz
LED backlight: Yes
Support HD: 720p HD
Brightness: 220 cd/m2
Contrast: 3000:1
Viewing Angle: 160°
Pixel response time: 8.5 ms
Progressive scan: Yes
Digital tuner: DVB-T, DVB-T2, DVB-C, DVB-S, DVB-S2
Number of channels: 1099
Teletext: there is
Multimedia: MP3, WMA, MPEG4, Xvid, MKV, JPEG
Sound stereo: there is
Sound Power: 12W (2x6W)
Acoustics: two speakers
Interface: AV, component, HDMI x2, USB
TV weight: 4 kg
TELEFUNKEN LED
Model: TF-LED32S74T2
Chassis/Version: TP.MS3663T.PB751
Panel: V320BJ6-Q01 320E66(CW3) REV.00
LED driver (backlight): integrated into MainBoard
PWM LED driver: OB3353CP
MOSFET LED driver: TO-252
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MOSFET Power: TO-252
MainBoard: TP.MS3663T.PB751
IC MainBoard: CPU: MSD3663LSAT, SPI Flash: 25Q64
MainBoard: XF-3SET-HP & SAT
General recommendations for LCD LED TV repair
Possible defects
- TELEFUNKEN TF-LED32S74T2 doesn't turn ON, the buttons and remote control don't respond and the indicators on the front panel are not glowing or blinking.
In this case the problem may be the main source of power supply - AC/DC converter, elements of which in this model are located on the common MainBoard TP.MS3663T.PB751. It is necessary to measure its secondary output voltages, and if not, check the power switches (TO-252) and the rectifier diodes in the converters for short circuits.
At breakdown of semiconductors in the secondary circuits of any converter, as a rule, it can operate in the emergency short-circuit mode without output voltages, and at short circuit in the elements of the primary circuit most often immediately burst the mains fuse and less often the current sensor at the source of the key.
Breakdown of Mos-Fet switches, used in pulse sources, is often caused by failure of other elements, for example, in PWM regulator supply circuit, in frequency-retaining or damping circuits, as well as in the Negative Feedback Stabilization. PWM chips (PWM) PWM SOT23-6 are usually checked by replacing them with new ones or with ones known to be in good working order.
- No picture, sound is there, remote control responds. Or the image may appear for a second and then immediately disappear.
The problem in these cases is usually the most probable in the nodes of the display matrix backlight. The cause of this may be a break in the circuit of the LEDs, or a problem in stabilizing their power supply.
Without a special current source it is impossible to check the line of LEDs in series, and it is not safe to use any voltage sources over 12v for this purpose. The only thing you have to do is to open the panel and check each LED separately. Usually Chinese multimeters with 9V power supply will light up one 3 volt LED a bit if you connect the probes to it in forward direction, red probe to anode, black probe to cathode. For twin 6-volt LEDs, the PN junction of its faulty regulator can be used as an indicator of the health of the LED. If the LED is faulty, its regulator will either be open or shorted.
If TELEFUNKEN TF-LED32S74T2 has no picture but you have sound, often the display backlight of V320BJ6-Q01 320E66(CW3) REV.00 is simply not working. Moreover, in LED TVs, the LEDs inside the panel usually fail, more rarely the LED driver.
In such cases you can see a faintly visible image when external light hits the screen.
To replace the LEDs requires disassembly of the LCD panel V320BJ6-Q01 - the process requiring a master of experience and expertise. We do not recommend 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 backlighting 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.MS3663T.PB751 is also faulty, 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.MS3663T.PB751, 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.
- Front panel LED is blinking, TV set does not turn on, remote control is unresponsive.
Repair or diagnostic of the TP.MS3663T.PB751 motherboard begins with checking the stabilizers and power converters needed 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 repairmen. To do this, you should check and, if necessary, replace elements CPU: MSD3663LSAT, SPI Flash: 25Q64. BGA chips failures are usually easy to detect with heating method.
If the TV works normally from external devices, but does not tune to the TV channels, the XF-3SET-HP & SAT tuner might be defective. In these cases you should first check if there is power to the corresponding pins of the XF-3SET-HP & SAT. Also make sure that the tuner and the processor are communicating via the I2C bus. Sometimes the tuner malfunction can be caused by a software malfunction.
Once again, users must be reminded! Trying to repair your TELEFUNKEN TF-LED32S74T2 without proper skill and experience may result in its total inoperability.
DOWNLOAD SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> Chassis TP.MS3663T.PB751.
DOWNLOAD FIRMWARE FOR SPI FLASH -----------> TELEFUNKEN TF-LED32S74T2, Main: TP.MS3663T.PB751, Panel: V320BJ6-Q01 320E66(CW3) REV.00.
Refinement after the repair of the backlight. TP.MS3663T.PB751, OB3353CP. Information from the master.
Reduce backlight current from 530 mA to 270 mA - removed two 1.6 Ohm resistors in the driver current sensor on the TP.MS3663T.PB751 board, leaving two 1.5 Ohms.
Limiting the driver current. TP.MS3663T.PB751. General information.
On TV's with TP.MS3663T.PB751 board and OB3353CP LED driver chip you must increase the total resistance of the four current sensor resistors connected in parallel, RB837, RB838, RB839, RB840, to reduce the backlighting current. You can remove one or two of them, or increase the ratings, then the total resistance of the sensor will increase and the backlight current will decrease proportionally.
TP.MS3663T.PB751 current backlight.
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 repairs
The MainBoard TP.MS3663T.PB751 is shown in the illustration below:
TP.MS3663T.PB751
The main features of the TELEFUNKEN TF-LED32S74T2:
A matrix (LED panel) V320BJ6-Q01 320E66(CW3) REV.00 is installed.
A converter combined with the main board TP.MS3663T.PB751, controlled by the PWM controller OB3353CP, is used to power the backlight LEDs. 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 module TP.MS3663T.PB751, with the use of chip CPU: MSD3663LSAT, SPI Flash: 25Q64 and others.
The XF-3SET-HP & SAT tuner provides TV reception and channel tuning.
More technical information about this panel:
Brand : CHIMEI INNOLUX
Model : V320BJ6-Q01
Type : A-Si TFT-LCD, CELL
Diagonal size : 31.5 inch
Resolution : 1366x768, WXGA
Display Mode : MVA, Normally Black, Transmissive
Active Area : 697.685x392.256 mm
Surface : Antiglare (Haze 2%)
Transmissivity : 6.0% (with Polarizer)
Contrast Ratio : 3000:1
Display Colors : 16.7M (6-bit + Hi-FRC)
Response Time : 8.5 (G to G)
Frequency : 60Hz
Signal Interface : LVDS (1 ch, 8-bit), 30 pins
Voltage : 12.0V
TELEFUNKEN TF-LED32S74T2 LCD TV set V320BJ6-Q01 31.5" (80cm) diagonal 16:9 size. The screen luminance of 220 cd/m² is provided by an LED backlight. Contrast, as the ratio of maximum brightness to minimum brightness, is 3000:1. The screen technology of this TV model features LED backlighting.
Matrix V320BJ6-Q01 and MainBoard software TP.MS3663T.PB751 implement HD image quality at a resolution of 1366x768 pixels in 720p (HD Ready). Supported multimedia file formats are MP3, WMA, MPEG4, Xvid, MKV, JPEG.
The speaker system has a sound power of 12 W (2x6 W) provided by the two speakers. NICAM STEREO audio processing system is used.
External interface (communication with other devices) is supported by standard inputs and outputs: antenna input (RF), AV, component, HDMI x2, USB. The digital tuner is capable of receiving DVB-T, DVB-T2, DVB-C, DVB-S, DVB-S2 TV channels.
The power supply is used as part of the MainBoard.
Overall dimensions: 732x481x195 mm.
TV weight: 4 kg.
Warning. The V320BJ6-Q01 320E66(CW3) REV.00 LED TV TELEFUNKEN TF-LED32S74T2 is an expensive and unreliable component.
Do not apply any impact to the glass and do not exert any pressure on the screen surface to avoid damaging the LED panel!
Also it is not safe to get liquid on the screen. Sometimes one drop is enough, if it drips down the glass onto the flat cables to make the TV set unrepairable.