Saturday 28 December 2019

REPAIRING / SERVICING TV SAMSUNG LE40S81B

Technical description and composition of the SAMSUNG LE40S81B TV, panel type and applicable modules. The composition of the modules.
SAMSUNG
Model: LE40S81B LE40S81BS
Chassis / Version: GJA40SEU
Panel: T400XW01 V0
T-CON: 4046HDCP2L V0.6 320AB02CP2L V03 LMX4122TO; 24C64.
Inverter (backlight): integrated into PSU + 4H.V2358.001, 4H.V2358.011
PWM Inverter: LX1691A
Power Supply (PSU): BN44-00165A // BN44-00165B // BN44-00134D
PWM Power: DM0365R (Standby), FAN7382, ICE2BS01, ICE1PCS02 (PFC)
MOSFET Power: 13N50CF, FQPF9N50C
MainBoard: BN41-00878A BN94-01194Q
IC MainBoard: CPU: MT8293AE; Scaler: SDP64; SOUND: NTP-3000
Tuner: BN40-00099A
Control: IR: BN41-00850A
Specifications LE40S81B
SAMSUNG LE40S81B
General repair guidelines for TV LCD
Possible malfunctions
- SAMSUNG LE40S81B does not turn on. There are no signs of operability. The indicators on the front panel do not light or flash, the TV does not respond to the remote control and control buttons.
Usually with such manifestations, the defect is caused by faulty elements in the main power module BN44-00165A. It is necessary to measure its output voltages, and in case of their absence (full or partial), it is necessary to check the serviceability of power switches (13N50CF, FQPF9N50C) of converters and rectifier diodes for possible short circuit.
In case of any breakdowns in the secondary circuits, the converter can operate in emergency short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key more often 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 microcircuits (PWM) DM0365R (Standby), FAN7382, ICE2BS01, ICE1PCS02 (PFC) are usually checked by replacing with new, 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.
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 the inverter.After checking all the electrolytic capacitors of the filters that are involved in the power supply of the inverter, you must ring in its converter power keys for breakdown and secondary windings of transformers for an open.
If in diagnosing a malfunction, it is necessary to disable the inverter protection, there is a risk of failure of the power elements of the inverter, and special care is required during operations, and after their completion, it is necessary to restore the protection circuits for further safe operation of the TV by the owner in normal mode.
- The indicator on the front panel blinks, the TV does not turn on in the operating mode, it does not respond to the remote control.
Repair or diagnostics of the BN41-00878A motherboard should begin by checking the stabilizers and power converters needed to power the microcircuits and matrix. If necessary, you should update or replace the software (software). Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - CPU: MT8293AE; Scaler: SDP64; SOUND: NTP-3000 and failed chips should be replaced with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board. Typically, such defects are detected by local heating of the chip.
If a tuner BN40-00099A is suspected of malfunction, first of all, it is necessary to verify the correctness of the software, as well as the presence of the necessary voltage levels and impulses of data exchange with the processor via the I2C bus at the corresponding terminals of the tuner.
Attention to users! Self-repair of a SAMSUNG LE40S81B TV without the appropriate qualifications and necessary experience can lead to its complete non-repairability!

SCHEMATIC ----------->  Samsung Chassis GJA26SEU-GJA46SEU.

FOR MODELS -------> Samsung LE26S81BX, LE26S86BD, LE32S81BX, LE32S86BD, LE37S81BX, LE40S81BX, LE40S86BD, LE46S81BX



SCHEMATIC -----------> Samsung Chassis GJA26TSA-GJA46TSA.

FOR MODELS -------> Samsung LE26S81BHX, LE32S81BHX, LE37S81BHX, LE40S81BHX, LE46S81BHX


 The appearance of the MainBoard BN41-00878A is shown in the figure below:
BN41-00878A
BN41-00878A can be used in TVs:
SAMSUNG LE26R81BX LE26R81B LE26R81BS (Panel T260XW02 V.5), SAMSUNG LE26S81BS (Panel V260B1-L04 Rev. C1), SAMSUNG LE32S81B (Panel T315XW02), SAMSUNG LE32S81B (Panel V315B1-L01381, LT01301, LT01BC, Rev. SAMSUNG LE46S81B (Panel LTA460WT-L15 0T1), SAMSUNG LE46S81B (Panel LTA460WT-L15), SAMSUNG LE23R81W (Panel T230XW01 V.1), SAMSUNG LE26R82B (Panel T260XW02 V.5), SAMSUNG LE231XB01BW1B231BWBB81B23B81B23B81B23B81B23BX1B231
PSU Advanced
According to the conditions of compliance with modern world standards for household switching power supplies, the BN44-00165A module provides for the use of a Power Factor Correction unit. The PFC circuit is a flyback converter based on the ICE1PCS02 PWM controller. The reactance of an electrolytic capacitor of a line filter at a frequency of 50-60 Hz is usually not more than 20-30 ohms and its charge directly from the network through open diodes could reach tens of amperes per pulse if no filtering were applied.
As a result of the PFC conversion, an increased voltage on the capacitor (about 380V) cannot directly open the rectifier diodes, on the anode of which the voltage will always be slightly less (about 300V) and then its charging current will always be limited by the elements of the PWM controller. As a result, the envelope of the high-frequency pulses of the consumed current will repeat the shape and phase of the input sinusoidal voltage. The presence of an increased voltage (+ 380V) on the mains capacitor indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the SAMSUNG LE40S81B device:
Installed matrix (LCD-panel) T400XW01 V0.
The matrix control uses the Timing Controller (T-CON) 4046HDCP2L.
To power the backlight, a converter is used, combined with the power supply, controlled by the LX1691A PWM controller.
The necessary supply voltages for all nodes of the SAMSUNG LE40S81B TV are generated by the power module BN44-00165A, or its analogs using microchips DM0365R (Standby), FAN7382, ICE2BS01, ICE1PCS02 (PFC) and power switches of the type 13N50CF, FQPF9N50C.
MainBoard - the main board (motherboard) is a BN41-00878A module, using CPU chips: MT8293AE; Scaler: SDP64; SOUND: NTP-3000 and others.
The tuner BN40-00099A provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: AUO
Model: T400XW01 V0
Type: a-Si TFT-LCD, Panel
Diagonal size: 40 inch
Resolution: 1366x768, WXGA
Display Mode: AMVA, Normally Black, Transmissive
Active Area: 885.168x497.664 mm
Surface: Antiglare, Hard coating (3H)
Brightness: 550 cd / m²
Contrast Ratio: 1500: 1
Display Colors: 16.7M (8-bit)
Response Time: 15/8 (Tr / Td); 8 (G to G)
Frequency: 60Hz
Lamp Type: CCFL Embedded (Balance board)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 5.0V