Saturday 28 December 2019

REPAIRING / SERVICING TV SAMSUNG LE40M87

Technical description and composition of the SAMSUNG LE40M87 TV, panel type and applicable modules. The composition of the modules.
SAMSUNG
Model: LE40M87 LE40M87BD
Chassis / Version: GTU40SEN
Panel: LTA400HT-LH1
T-CON: 13N50CF, FQPF9N50C
Inverter (backlight): integrated into PSU + SSB400HA20B
PWM Inverter: LX1691A
Trans Inverter: BL-1040 0719D
Power Supply (PSU): BN44-00165A - IP-231135A
PWM Power: DM0365R (Standby), FAN7382, ICE2BS01, ICE1PCS02 (PFC)
MOSFET Power: 13N50CF, FQPF9N50C
MainBoard: BN41-00813B - MP1.0
IC MainBoard: MST3560M-LF-170, SiI9125CTU, SVP-WX68, HYB25D256163CE, 24C256WP, NTP-3000
Tuner: BN40-00096A
Technical specifications LE40M87BD
SAMSUNG LE40M87
General repair guidelines for TV LCD
Repair of TVs, as well as other devices, it is advisable to start with an external examination. Visible damage to the elements can sometimes indicate the direction of the search for the defect even before the start of the necessary measurements. In some cases, faulty elements are visible to the naked eye, for example, charred resistors or swollen metal-ceramic capacitors, or electrolytic in rectifier filters. Ring cracks formed in the soldered terminals of transformers or heating elements of the circuit are also frequent sources of many malfunctions with a variety of external manifestations.
Malfunctions of the power module BN44-00165A - IP-231135A can be expressed in different ways, for example, SAMSUNG LE40M87 does not turn on at all and the control lights on its front panel do not light up and do not blink, there are no signs of operability. In the absence of swollen filter capacitors of the secondary rectifiers, the diagnostics of the power supply should be started by checking the fuse and, if it is broken, it is first necessary to check all the power semiconductor elements of the primary circuit - diodes and transistors 13N50CF, FQPF9N50C for the possibility of an avalanche or thermal breakdown.
It should be borne in mind that in the practice of repair it is extremely rare that key transistors in switching power supplies (SMPS) fail for no reason that should be sought by checking other components, for example, a key breakdown can provoke faulty elements of the damper circuits, or dried electrolytic capacitors or dangling primary resistors BP circuits involved in the stabilization process. In this case, all semiconductor elements of the strapping of the PWM regulator chip DM0365R (Standby), FAN7382, ICE2BS01, ICE1PCS02 (PFC), which it is desirable to check by replacement, are subject to verification.
If the SAMSUNG LE40M87 does not have an image, but there is sound, there is a possibility of a malfunction of the backlight or power converter. You should also make sure that the electrolytic capacitors of the secondary rectifiers of the common power supply are working. All necessary precautions must be observed when disabling the inverter protection during diagnostics and not leaving it disconnected after the repair is completed.
Diagnosis and repair of the BN41-00813B - MP1.0 motherboard usually begins with a test of the operation of the stabilizers and power converters of the module chips. In some cases, a software update is required. If it is not possible to replace the MB board (SSB), you need to check the health of its elements - M308A0SGP, 24C256, NTP-3000. Defective components should be replaced.
Before changing the tuner BN40-00096A, if it is not possible to tune to television channels, make sure that there are supply voltages that must be measured at the corresponding terminals of the tuner and check the software for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
Owners and users of the SAMSUNG LE40M87 TV must remember that self-repair without special knowledge, skills and qualifications can be fraught with negative consequences that can lead to complete non-repairability of the device!


SCHEMATIC --------> Samsung LLE37M87BDX, LE40M87BDX, LE46M87BDX, LE52M87BDX Chassis GTU37SEN, GTU40SEN, GTU46SEN, GTU52SEN.

PSU SCHEMATIC ----->  BN44-00165A.

The appearance of the MainBoard BN41-00813B is shown in the figure below:
BN41-00813B
BN41-00813B can be used in TVs:
SAMSUNG LE37M87BD (Panel T370HW02 V.2), SAMSUNG LE46M87BD (Panel LTA460HT-LH2), SAMSUNG LE40M87 LE40M87BD (Panel LTA400HT-LH1).
PSU Advanced
The power module BN44-00165A is made using the Power Factor Correction (PFC) scheme to eliminate multiple AC harmonics introduced by the device into the mains. The PFC node is a Step-Up Converter based on the ICE1PCS02 PWM controller, which evenly distributes high-frequency impulses of the charging current of the electrolytic capacitor of the rectifier filter of the mains voltage over a period of 50 Hz. The current of its charge in this case will already be determined not by its reactance (usually 10-30 ohms for the network frequency), but by the elements of the converter. As a result, a change in the amplitude of the pulses (envelope) of the consumed current of the converter will repeat the shape and phase of the input sinusoidal voltage. The availability of the increased voltage (about + 380V) in the operating mode on the capacitor of the line filter indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the SAMSUNG LE40M87 device:
Installed matrix (LCD panel) LTA400HT-LH1.
The matrix control uses the Timing Controller (T-CON) 13N50CF.
To power the backlight, a converter is used, combined with the power supply, controlled by the LX1691A PWM controller. A transformer BL-1040 0719D is installed in the inverter converter.
The necessary supply voltages for all nodes of the TV SAMSUNG LE40M87 are formed 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 BN41-00813B module, using microcircuits MST3560M-LF-170, SiI9125CTU, SVP-WX68, HYB25D256163CE, 24C256WP, NTP-3000 and others.
The tuner BN40-00096A provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: SAMSUNG
Model: LTA400HT-LH1
Type: a-Si TFT-LCD, Panel
Diagonal size: 40 inch
Resolution: 1920x1080, FHD
Display Mode: S-PVA, Normally Black, Transmissive
Active Area: 885.6x498.15 mm
Surface: Antiglare (Haze 2.4%), Hard coating (3H)
Brightness: 600 cd / m²
Contrast Ratio: 2000: 1
Display Colors: 1.07B (10-bit), CIE1931 92%
Response Time: 10/6 (Tr / Td)
Frequency: 60Hz
Lamp Type: 20 pcs CCFL Embedded (Balance board)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V