Thursday 2 January 2020

REPAIR / SERVICING TV SAMSUNG UE28F4020AW

Technical description and composition of the SAMSUNG UE28F4020AW TV, panel type and applicable modules. The composition of the modules.
SAMSUNG LED
Model: UE28F4020AW
Chassis / Version: Ver. Rh04
Panel: HF280AGH-R1
LED backlight: 8LED 2013SVS28H 8 REV1.8 130103 (4pcs)
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 BN94-06546P
IC MainBoard: CPU: SENK13
Tuner: BN40-00255A DTOS40EIL035A
Control: BN59-00741A
Technical Specifications UE28F4020
SAMSUNG UE28F4020AW
General repair guidelines for TV LCD LED
If the UE28F4020AW TV does not turn on, does not respond to the remote control and buttons on the front panel, does not blink lights and does not show any signs of operability, the BN44-00644D power supply module is probably faulty in this case. After checking the mains fuse and power elements of the primary power supply circuit, you should also check for the presence of a short circuit in the loads of the secondary rectifiers.
In most cases, key breakdowns in switching power supplies (SMPS) do not occur for no reason and you should look for other faulty circuit elements that could provoke a defect. This can be dried electrolytic capacitors in the primary circuit, and faulty damper elements, as well as dangling resistors or punched semiconductor elements in the stabilization circuits. Possible defective PWM chip from the manufacturer.
In cases where the SAMSUNG UE28F4020AW TV has lost its image, and the sound is there and all other functions are operational, there is a possibility of a LED driver malfunction (a converter for powering the HF280AGH-R1 backlight LEDs, in which the 8LED 2013SVS28H 8 REV1.8 LED strips are installed). When you turn on the TV, the image may appear briefly and disappear. It must be borne in mind that with such manifestations the LEDs themselves also fail.
In case of breaks in the LED circuit, a complete disassembly of the panel is required, the LEDs are checked for breakage, as well as the reliability of the connections in the connectors and the rations of the terminals.
It should be remembered that it is not possible to determine the break in the LED lines without disassembling the panels with a tester or multimeter without an additional device, for example, a current source. To open all PN junctions connected in series at once, a voltage of several tens of volts may be required.
If the motherboard BN41-01987A BN94-06546P is faulty, first of all it is necessary to check all the linear stabilizers and power converters of its chips, and also, if necessary, update the software (software). Sometimes you can check the health of MB only by replacement.
Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Checking or replacing CPU elements: SENK13 requires the necessary training and professional skills to repair modules at the component level. Problems associated with the use of BGA soldering technologies can be diagnosed by warming up.

If the TV works normally from external devices, but does not tune into television channels, the tuner BN40-00255A DTOS40EIL035A may be malfunctioning. In such cases, first of all, you should make sure that there are supply voltages at its corresponding terminals. Sometimes the cause of the inoperability of the tuner may be a software failure.
Attention to the owners! Attempts to repair the TV SAMSUNG UE28F4020AW on its own are not recommended by the manufacturer and can lead to serious negative consequences!


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 UE28F4020AW device:
Installed matrix (LED-panel) HF280AGH-R1.
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 necessary supply voltages for all nodes of the SAMSUNG UE28F4020AW TV are generated 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 CPU chips: SENK13 and others.
The tuner BN40-00255A DTOS40EIL035A provides the reception of television programs and tuning to channels.