Saturday 28 December 2019

REPAIRING / SERVICING TV SAMSUNG LE40D551

Technical description and composition of the SAMSUNG LE40D551 TV, panel type and applicable modules. The composition of the modules.
SAMSUNG
Model: LE40D551 LE40D551K2W
Panel: LTF400HM03
Inverter (backlight): SST400_12A01 INV40T12A REV0.1
Power Supply (PSU): BN44-00440A REV1.1 I40F1_BSM
PWM Power: ICE3BR1765J (Standby), SEM3040 (PFC), UCC25600
MOSFET Power: TK8A50D, FDPF12N50UT
MainBoard: BN41-01603C BN94-05106B // BN41-01751A BN94-05412Q
IC MainBoard: K9F1G08U0D, 25Q40,24C256, K4B1G1646G-BCH9, D23330AC, WT61P805, DRV612
Tuner: BN40-00197A
Control: Remote: AA59-00484A, IR: BN96-16729F (BN41-01600B) D550-12C
Technical specifications LE40D551
SAMSUNG LE40D551
General repair guidelines for TV LCD
Possible manifestations of defects
- The SAMSUNG LE40D551 TV does not turn on and does not show any signs of turning on, it does not respond to the control buttons or the remote control.
With such manifestations, in some cases, the BN44-00440A power module is faulty. It is necessary to measure its output voltages and, if they are absent, check the power switches (TK8A50D, FDPF12N50UT) and rectifier diodes for the probability of short circuit in the converters.
In the event of breakdowns in the secondary circuits of the converter, it can usually fail in short circuit mode, and in the event of a short circuit in the power elements of the primary circuit, the mains fuse or current sensor at the source of the key most often breaks.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM) ICE3BR1765J (Standby), SEM3040 (PFC), UCC25600, in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- 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.
The defect can be caused by problems in the nodes or elements of the backlight of the display, or in the power supply of the lamps or inverter. If all the electrolytic capacitors of the filter for the power supply of the inverter are working, make sure that the lamps are working, then you need to check the converter keys and the secondary windings of the transformers.
Sometimes, for diagnostic purposes, it is necessary to disable the inverter protection. In such cases, special care must be taken during work, and the protection circuits should be restored immediately after the repair is completed.
- The indicator blinks or glows constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the BN41-01603C motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, you should update or replace the software (software). In cases of complex repairs of MB (SSB) and in the presence of the necessary skills and equipment, sometimes it may be necessary to replace its chips WT61P805, Eeprom: 24C256 and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
If the TV works normally from external devices, but does not tune into television channels, the tuner BN40-00197A may be malfunctioning. In such cases, first of all, you should make sure that there are supply voltages at its corresponding terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the cause of the inoperability of the tuner may be a software failure.
Attention TV owners! Attempts to self-repair SAMSUNG LE40D551 are not recommended by the manufacturer and can lead to serious negative consequences!


The appearance of the MainBoard BN41-01603C is shown in the figure below:
BN41-01603C
BN41-01603C can be used in TVs:
SAMSUNG LE32D451 LE32D451G3W (Panel T315XW03 VD), SAMSUNG LE40D550K1W LE40D550 (Panel LTF400HM03), SAMSUNG LE26D451 LE26D451G3W (Panel T260XW04 V.8), SAMSUNG LE40D551 LE40D551K2W (Panel LTF400HM03), SAMSUNG LE32D450 LE32D450G1W (Panel T315XW03 VD), SAMSUNG LE37D550 LE37D550K1W (Panel T370HW03 VP).
The appearance of the power supply
Main features of the SAMSUNG LE40D551 device:
Installed matrix (LCD-panel) LTF400HM03.
The inverter SST400_12A01 is used to power the backlight.
The necessary supply voltages for all nodes of the SAMSUNG LE40D551 TV are generated by the BN44-00440A power module or its analogs using ICE3BR1765J (Standby), SEM3040 (PFC), UCC25600 microcircuits and TK8A50D, FDPF12N50UT power switches.
MainBoard - the main board (motherboard) is a module BN41-01603C, using microchips K9F1G08U0D, 25Q40,24C256, K4B1G1646G-BCH9, D23330AC, WT61P805, DRV612 and others.
The tuner BN40-00197A provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: SAMSUNG
Model: LTF400HM03-V02
Type: a-Si TFT-LCD, Panel
Diagonal size: 40 inch
Resolution: 1920x1080, FHD
Display Mode: SPVA, Normally Black, Transmissive
Active Area: 885.6x498.15 mm
Surface: Antiglare (Haze 5.5%), Hard coating
Brightness: 450 cd / m²
Contrast Ratio: 5000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 8 (G to G)
Frequency: 60Hz
Lamp Type: 12 pcs CCFL Embedded (Balance board)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V