Thursday, 2 January 2020

REPAIR / SERVICING TV SAMSUNG UE28F4000

Technical description and composition of the SAMSUNG UE28F4000 TV, panel type and applicable modules. The composition of the modules.
SAMSUNG LED
Model: UE28F4000 UE28F4000AW
Chassis / Version: LH04
Panel: HF280AGH-C1
LED backlight: LUMENS D2GE-280SC0-R3 [12,12,27]
T-CON: ST2751A01-3-XC-2
LED driver (backlight): integrated into PSU; 103V 230mA
Power Supply (PSU): BN44-00644D L28S0_DHS
PWM Power: SQD2011K
MOSFET Power: 60R360N
MainBoard: BN41-01987A BN94-06272G
IC MainBoard: SENK13, 25Q40CLSIP, 24C256, K4B1G1646G-BCKO, TPS54328, NTP-7412S
Tuner: BN44-00255A
Control: IR: BN41-01976B
Technical Specifications UE28F4000
SAMSUNG UE28F4000
General repair guidelines for TV LCD LED
Possible malfunctions
- SAMSUNG UE28F4000 TV does not turn on, does not respond to the remote control and control panel buttons, indicators do not light up and do not blink.
Most likely in this case, the main switching power supply (IIP) BN44-00644D is faulty. It is necessary to measure its output supply voltages, and in case of their absence, check the serviceability of the power switches (60R360N) of the converters and rectifier diodes for the probability of breakdown in PN semiconductor junctions.
In case of breakdowns in the secondary circuits, the converter, as a rule, can emergency work in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse usually breaks.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, in the power supply circuit of a PWM controller, in frequency-setting or damping circuits, as well as in Negative Stabilization Feedback. PWM chips PQM SQD2011K are usually checked by replacing with new ones, or obviously working.
- There is no image, but there is sound and reaction to commands from the remote control. Or the image appears immediately after turning on and disappears.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It is impossible to check the LED line for breaks without disassembling the panel with a multimeter or tester. For these purposes, it is necessary to open all series-connected PN junctions and a voltage of the order of tens of volts will be required, and ideally, a current source. Having disassembled the panel, it is necessary to check each LED separately. Chinese multimeters, as a rule, light up a single 3-volt LED in the forward direction. In the case of using dual 6-volt LEDs, the PN junction of its protective zener diode can serve as an indicator of serviceability. In faulty LEDs, the zener diode will either be cut off or broken into short-circuit.
- The TV does not turn on, the indicator signals standby or working mode, or blinks.
Repair or diagnostics of the BN41-01987A motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Checking or replacing elements SENK13, 25Q40CLSIP, K4B1G1646G-BCKO, TPS54328, NTP-7412S requires the necessary training and professional skills in repairing modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by warming up.
Before replacing the tuner BN44-00255A, if there is no tuning to the channels, you must first check the software and the supply voltage at its terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus
It should be remembered! Attempts to self-repair a SAMSUNG UE28F4000 TV, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!


FIRMWARE SPI FLASH, EEPROM -----------> SAMSUNG UE28F4000 UE28F4000AW LH04, Main: BN41-01987A BN94-06272G, Panel: HF280AGH-C1.

UE28H4000AK - UE28H4000AKXRU - RS01:
Panel: HH028AGH-R1,
T-CON: ST2751A01-3-XC-3,
Backlight: SAMSUNG_2014SVS28_3228_06_REV1.1_131108,
Main: BN41-02105A BN94-07207T,
POWER: BN44-00695A L28S0_ESM PSLF490S06A,
Remote: BN59-00741A.

FIRMWARE SPI FLASH -----------> SAMSUNG UE28F4000 UE28F4000AW LH04, Main: BN41-02105A



The appearance of the MainBoard BN41-01987A is shown in the figure below:
BN41-01987A
BN41-01987A can be used in TVs:
SAMSUNG UE28F4020AW (Panel HF280AGH-R1), SAMSUNG LT27C370EX (Panel LTM270HL01), SAMSUNG UE22F5000 UE22F5000AK (Panel M215HW03 V.1), SAMSUNG UE28F4000 UE28F4000AW-C1 H2.
The appearance of the power supply
Main features of the SAMSUNG UE28F4000 device:
Installed matrix (LED-panel) HF280AGH-C1.
The matrix control uses the Timing Controller (T-CON) ST2751A01-3-XC-2.
To power the backlight LEDs, a converter is used, combined with a power supply.
The formation of the necessary supply voltages for all nodes of the SAMSUNG UE28F4000 TV is carried out by the BN44-00644D power module, or its analogs using SQD2011K microcircuits and power switches of the 60R360N type.
MainBoard - the main board (motherboard) is a BN41-01987A module, using microchips SENK13, 25Q40CLSIP, 24C256, K4B1G1646G-BCKO, TPS54328, NTP-7412S and others.
The tuner BN44-00255A provides the reception of television programs and tuning to channels.