Thursday, 2 January 2020

REPAIR / SERVICING TV SAMSUNG UE24H4070

Technical description and composition of the SAMSUNG UE24H4070 TV, panel type and applicable modules. The composition of the modules.
SAMSUNG LED
Model: UE24H4070 UE24H4070AU
Chassis / Version: Ver: CP01
Panel: V236BJ1-LE2
LED backlight: V236B1-LE2-TREM11 27 leds
LED driver (backlight): integrated into PSU; 35-55V 200mA
PWM LED driver: BD93941FP
MOSFET LED driver: MDD1905
Power Supply (PSU): BN44-00746C L23S0DS
PWM Power: SSC3S111
MOSFET Power: 8N60
MainBoard: BN41-02251A BN94-07150H
IC MainBoard: K482G1646Q-BCK0, DRV612
Tuner: BN40-00281A DTOS40EIL276A
Control: IR: BN41-01976B
Technical Specifications UE24H4070
SAMSUNG UE24H4070
General repair guidelines for TV LCD LED
Possible manifestations of defects
- SAMSUNG UE24H4070 TV does not turn on at all. There is no reaction to the remote control and control buttons from the front panel. Indicator lights do not light or flash.
Most likely in this case, the main switching power supply (IIP) BN44-00746C is faulty. It is necessary to measure its output voltages and, in case of their absence, check the serviceability of power switches (8N60) and rectifier diodes in the converters for possible breakdown.
In case of breakdowns of the diodes in the secondary circuits, the converter can operate in emergency short circuit mode without output voltages, and during short circuit in the power elements of the primary circuit, the mains fuse and / or current sensor at the source of the key 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 SSC3S111, in the absence of visible damage or frank fault between the terminals, are checked by replacing with new, 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.
The most likely in these cases is a malfunction of the LED backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
To detect a break in the LED lines without disassembling the panel, a current source is required. It is impossible to open transitions connected in series with a simple multimeter; voltage of several tens of volts is necessary.
- The TV does not turn on, the indicator signals standby or working mode, or blinks.
Repair or diagnostics of the BN41-02251A 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 cases of attempts to repair the MB board (SSB), it is necessary to check the serviceability of its elements - K482G1646Q-BCK0, DRV612 which may require replacement with new ones. If the BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its conclusions with the board (it is diagnosed by heating).
Before replacing the BN40-00281A DTOS40EIL276A tuner, if there is no tuning for the channels, 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
Once again, remind users! Attempts to self-repair a SAMSUNG UE24H4070 TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!



The appearance of the MainBoard BN41-02251A is shown in the figure below:
BN41-02251A
BN41-02251A can be used in TVs:
SAMSUNG UE24H4070 UE24H4070AU (Panel V236BJ1-LE2), SAMSUNG UE24H4080 UE24H4080AU (Panel V236BJ1-LE2).
The appearance of the power supply
Main features of the SAMSUNG UE24H4070 device:
Installed matrix (LED-panel) V236BJ1-LE2.
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by the BD93941FP PWM controller. As power elements of the LED driver, keys of the MDD1905 type are used.
The necessary supply voltages for all nodes of the SAMSUNG UE24H4070 TV are generated by the BN44-00746C power module or its analogs using SSC3S111 microcircuits and 8N60 type power switches.
MainBoard - the main board (motherboard) is a module BN41-02251A, using microchips K482G1646Q-BCK0, DRV612 and others.
Tuner BN40-00281A DTOS40EIL276A provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: CHIMEI INNOLUX
Model: V236BJ1-LE2
Type: a-Si TFT-LCD, Panel
Diagonal size: 23.6 inch
Resolution: 1366x768, WXGA
Display Mode: Super MVA, Normally Black, Transmissive
Active Area: 521.471x293.184 mm
Surface: Antiglare (Haze 1%), Hard coating (3H)
Brightness: 250 cd / m²
Contrast Ratio: 3000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 8.5 (G to G)
Frequency: 60Hz
Lamp Type: WLED Without Driver
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V