Thursday, 2 January 2020

REPAIR / SERVICING TV SAMSUNG UE28J4100AK

Technical description and composition of the SAMSUNG UE28J4100AK TV, panel type and applicable modules. The composition of the modules.
SAMSUNG LED
Model: UE28J4100AK UE28J4100A
Chassis / Version: LS02
Panel: HH028AGH-R2 ST2751A02-1
LED backlight: D4GE-280DC0-R2 [03/14/17]
T-CON: T2751A02-1-XC-2
LED driver (backlight): integrated into PSU; 63V 350mA
Power Supply (PSU): BN44-00695A L28S0_ESM PSLF490S06A
PWM Power: S3330 (FAN6755)
MOSFET Power: MMF60R580P
MainBoard: BN41-02105A BN94-09059Q
IC MainBoard: CPU: NT14L, Spi Flash W25Q40BL, Eeprom AT24C256, Audio: NTP7414
Tuner: BN40-00287A
Appearance
SAMSUNG UE28J4100AK
General repair guidelines for TV LCD LED
Possible malfunctions
- The SAMSUNG UE28J4100AK TV does not turn on, does not respond to the remote control and the control panel buttons, the indicators do not light or flash.
Most likely in this case, the main switching power supply (MPS) BN44-00695A is faulty. It is necessary to verify the presence of its output voltages and, if they are completely absent, check the power switches (MMF60R580P) and rectifier diodes for a probable short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during short circuit in the elements of the primary circuit, the mains fuse usually breaks.
Mos-Fet power switches used in switching power supplies sometimes fail due to a malfunction of any other elements that can put it out of operation in key mode or create an excess of the maximum permissible key parameters. These can be elements supplying the PWM controller, frequency-setting or damping circuits, or negative feedback elements in the stabilization circuit. PWM controllers S3330 (FAN6755), in the absence of visible damage or obvious short-circuit between the terminals, are checked by replacing with new ones, or obviously working.
- There is no image, there is sound, it responds to the remote control, the channels are switched. In some cases, the image appears when you turn on and immediately 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 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. Then it is necessary to open the panel and check each LED separately with a multimeter. If the capabilities of your multimeter do not allow you to open the LED in the forward direction or dual LEd are used, then the PN junction of the emergency zener diode can indirectly serve as a health indicator. In case of LED-a malfunction, the zener diode PN junction will either be cut off or broken into short-circuit.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the BN41-02105A 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). In some cases, to repair the MB (SSB) board, it may be necessary to replace the chips - CPU: NT14L, Spi Flash W25Q40BL, Eeprom AT24C256, Audio: NTP7414 with new or obviously working ones. In cases where BGA technologies are used, defects are usually localized by the heating method.
If there is no reception of television channels, but the TV is working properly from external devices, first of all, check the voltage of the tuner BN40-00287A and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
Attention TV owners! Attempts at self-repair of SAMSUNG UE28J4100AK are not recommended by the manufacturer and can lead to serious negative consequences!



The appearance of the MainBoard BN41-02105A is shown in the figure below:
BN41-02105A
BN41-02105A can be used in TVs:
SAMSUNG T24D310EX (Panel V236BJ1-LE2 REV.C5), SAMSUNG UE28H4000AK (Panel HH028AAGH-R1), SAMSUNG T28D310EX (Panel HH028AGH-R2), SAMSUNG UE22H5000 UE22H5000AK (Panel MG28HT28) UE28J4100AK UE28J4100A (Panel HH028AGH-R2 ST2751A02-1).
The appearance of the power supply
Main features of the SAMSUNG UE28J4100AK device:
Installed matrix (LED panel) HH028AGH-R2 ST2751A02-1.
The matrix control uses the Timing Controller (T-CON) T2751A02-1-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 UE28J4100AK TV are generated by the BN44-00695A power module or its analogs using S3330 microcircuits (FAN6755) and power switches of the MMF60R580P type.
MainBoard - the main board (motherboard) is a BN41-02105A module, using CPU chips: NT14L, Spi Flash W25Q40BL, Eeprom AT24C256, Audio: NTP7414 and others.
The tuner BN40-00287A provides the reception of television programs and tuning to channels.