Saturday, 24 July 2021

REPAIRING / SERVICING TV TELEFUNKEN D32H277N3C

 Technical description and composition of the TELEFUNKEN D32H277N3C TV, type of panel and modules used. Module composition.
Composition Specifications
TELEFUNKEN D32H277N3C
TELEFUNKEN D32H277N3C

TELEFUNKEN LED Model: D32H277N3C

Chassis/Version: 17MB95M

Panel: VES315WNDB-2D-N02

T-CON: FAN6300

LED driver (backlight): integrated into PSU

PWM LED driver: MP3394S

MOSFET LED driver: FQD7N10L

Power Supply (PSU): 17IPS71

MOSFET Power: FQPF8N60C

MainBoard: 17MB95M

IC MainBoard: MT5820LUNU, 25L1605, H27U2G8F2CTR-BC, H5TQ2G63DFR
General advice about LCD LED TV repair
Possible defects

- TELEFUNKEN D32H277N3C doesn't turn on, buttons and remote control don't respond, indicators on the front panel don't glow or blink.

Usually with such manifestations the defect is caused by faulty elements in the main power module 17IPS71. Then you should measure its output voltages, and in case of their full or partial absence you should check the serviceability of the power switches (FQPF8N60C) and the inverter rectifier diodes for possible short circuits.
If there is a breakdown in the secondary circuits, the inverter can usually be short-circuited, and a short in the power elements of the primary circuit will usually blow the mains fuse.
Mos-Fet power switches used in switching power supplies sometimes fail due to the failure of any other elements that can take it out of key mode, or create an exceedance of the maximum allowable parameters of the switch. These can be the elements that feed the PWM controller, the frequency-retaining or damping circuits, or the negative feedback elements in the stabilization circuit. PWM controllers, if there is no visible damage or outright short circuits between pins, are checked by replacing with new or known good ones.

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

As a rule, in such cases there is no display backlight. The cause may be in the breakage of backlight LEDs, in the stabilization of their power, or in the violation of the contact connections of the string connectors.
It is impossible to detect a breakage in the line of LEDs without disassembling the panel with a simple multimeter. LEDs are connected in series and to open their junctions you will need a voltage of several tens of volts. Ideally a current source would be suitable for this purpose. You can open up the panel and check each LED separately. Usually, Chinese multimeters will light up one 3 volt LED slightly if you connect the probes to it in the forward direction (red probe to the anode, black probe to the cathode). For twin 6-volt LEDs, the PN junction of its faulty stabilizer can be used as an indicator of the health of the LED. If the LED is faulty, it will either be open or shorted.


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

- The TV set will not turn on, the LED will indicate standby or operation mode, or it will blink.

Repair or diagnosis of the 17MB95M motherboard should begin with checking the stabilizers and power converters needed to power the chips and matrix. If necessary, software (software) should be updated or replaced. Sometimes the following MainBoard parts need to be checked or replaced (if necessary): MT5820LUNU, 25L1605 , H27U2G8F2CTR-BC, H5TQ2G63DFR. If you use a BGA processor, its malfunction is usually diagnosed by local heating.

Warning to users! Unauthorized repair of TELEFUNKEN D32H277N3C without relevant qualification and necessary experience may lead to its total unrepairability!


DOWNLOAD SCHEMATIC DIAGRAM  / PSU SERVICE MANUAL   ------------------>    17IPS71-R3 Power supply.



DOWNLOAD FIRMWARE FOR SPI FLASH  ----------->   TELEFUNKEN D32H277N3C, Main: 17MB95M, Panel: VES315WNDB-2D-N02.


Refinement after repair of the backlight. 17IPS71, MP3394S. Information from the master.

Decreased backlight current from 240 mA to 160 mA - I replaced R113 resistor 2.7 kOhm to 6.2 kOhm on pin 6 of MP3394S LED driver on 17IPS71 power supply board.
Driver current limitation. 17IPS71, MP3394S. General advice.

To reduce backlight current in TV's with 17IPS71 power supply and MP3394S LED driver chip, increase the total resistance of the resistors from pin 6 (ISET) to the cabinet. It is sufficient to increase the rating of one of them, for example R113.
The maximum current in each channel (in milliamps) for resistor Rset (in kiloohms) will be determined from the ratio 790*1.23V/(Rset+0.4).
17IPS71 current backlight

A PDF document from the manufacturer of the ---------------->  MP3394S     is included.
 

More on MainBoard Repair

The MainBoard 17MB95M is shown in the illustration below:

17MB95M

17MB95M can be used in televisions:

TOSHIBA 40L5455R (Panel VES400UNVS-3D-N01), TOSHIBA 40L5435 40L5435DG (Panel VES400UNVS-3D-N01).


Power Supply Unit Appearance

The main features of the device TELEFUNKEN D32H277N3C:

A matrix (LED panel) VES315WNDB-2D-N02 is installed.
Timing Controller (T-CON) FAN6300 is used to control the matrix.
The converter combined with a power supply is used to power the backlight LEDs and is controlled by the MP3394S PWM controller. FQD7N10L switches are used as power elements of LED-driver.
The required supply voltages for all TELEFUNKEN D32H277N3C TV assemblies are generated by the 17IPS71 power supply module or its analogues with the use of FQPF8N60C power keys.
MainBoard - the main board (motherboard) is 17MB95M module, using MT5820LUNU, 25L1605, H27U2G8F2CTR-BC, H5TQ2G63DFR and other microchips.