Friday 27 December 2019

REPAIRING / SERVICING TV SAMSUNG LE40B550A5W

Technical description and composition of the SAMSUNG LE40B550A5W TV, panel type and applicable modules. The composition of the modules.
SAMSUNG
Model: LE40B550A5W
Chassis / Version: N68A
Panel: LTF400HA08
T-CON: FHD60C4L V1.1 .THF9301, 24C64WP, MAX9591, TPS65167A, I7814HS
Inverter (backlight): integrated into PSU
PWM Inverter: BD9893F (16), LM358F
Power Supply (PSU): BN44-00264C
PWM Power: FAN7530 (PFC), 3BR1065JF
MOSFET Power: F11NM60N, FQPF9N50C
MainBoard: BN94-02756D
IC MainBoard: ATMLH9362EB-1, ATMLH94402B-1, K4T51163QG-HCE7, I9287CNU, WM8593SEFT, STA339BW
Tuner: TDHG6-K12A
Control: BN59-00939A
SAMSUNG
Model: LE40B550A5W
Chassis / Version: N68A
Panel: LTF400HA08 A03
Inverter (backlight): integrated into PSU
PWM Inverter: BD9893
MOSFET Inverter: STP9NK50ZFP
Trans Inverter: 332430028EF, 332430029EF
Power Supply (PSU): BN44-00264C REV 1.3 (H40F1_9HS)
PWM Power: FAN7530 (PFC), 3BR1065JF
MOSFET Power: STF11NM60N (PFC)
MainBoard: BN41-01167B (MP1.1) BN94-02668M
IC MainBoard: SPI Flash: MX25L6405D
Tuner: TDHG6-K12A BN40-00145A
Specifications LE40B550
SAMSUNG LE40B550A5W
General repair guidelines for TV LCD
If the TV does not turn on, no indicators on its front panel are on or blinking, there is no reaction to the remote control and buttons, there are no sounds and any signs of operability when turned on, then there is a certain probability that the BN44-00264C power supply module and need repair. In this case, first of all, it is necessary to check the fuse at the mains input. If it is broken, then you should check for breakdown of the PN junctions rectifier bridge diodes and key transistors of the converters.
As a rule, MOSFET keys are quite reliable and rarely fail for no reason. The reasons for the breakdown of the keys should be sought by checking other components of the circuit - electrolytic capacitors, resistors and semiconductor elements of the primary circuit. PWM circuits are checked by replacing with obviously good ones.
When using a power factor correction unit (PFC) in the power modules, troubleshooting becomes somewhat more complicated and requires additional experience and knowledge of the device for their operation.
In cases where the SAMSUNG LE40B550A5W TV has lost an image, and the sound is there and all other functions are operational, there is a possibility of an inverter (converter for powering the backlight) malfunctioning. When you turn on the TV, the image may appear briefly and immediately disappear. It must be borne in mind that with such manifestations, the lamps themselves also fail, the malfunction of which can be detected by replacement, by connecting to the connectors for diagnostics that are known to be serviceable and suitable in power.
When repairing the inverter, it is often necessary for diagnostics to turn off the protection, which, for the purpose of fire safety, turns it off in any emergency situation, for example, during a malfunction or uneven wear of the lamps, which makes it difficult to find a defect.
It should be remembered that in such cases there is a risk of failure of the power elements of the inverter and to take special care. After carrying out repairs, the protection circuit must be restored for further safe operation of the TV.
Repair of the BN94-02568M motherboard must begin with the diagnosis and verification of all linear stabilizers or power converters of its microcircuits. Sometimes it may be necessary to update the software (software) - flashing FLASH or EEPROM.
Once again, remind users! Attempts to self-repair a SAMSUNG LE40B550A5W TV without the appropriate qualifications and experience can lead to its complete non-repairability!


SCHEMATICS ----->  Samsung LE40B550 Chassis N68A.
 
FOR MODELS-------->: LE32B55*, LE37B55*, LE40B55*, LE46B55*, LE32B65*, LE37B65*, LE40B65*, LE46B65*, LE55B65*, LE32B57*, LE37B57*, LE40B57*, LE46B57*, LE32B67*, LE37B67*, LE40B67*, LE46B67*, LE55B67*, LE40B62*, LE46B62*, LE52B62*, LE40B75*, LE46B75*, LE52B75*

PSU SCHEMATIC---------> BN44-00264C.


 The appearance of the MainBoard BN41-01167B is shown in the figure below:
BN41-01167B
BN41-01167B can be used in TVs:
SAMSUNG LE40B550A5W (Panel LTF400HA08 A03), SAMSUNG LE32B551A6W LE32B551 (Panel LTF320HA09), SAMSUNG LE40B653 LE40B653T5W (Panel T400HW02 V.5), SAMSUNG LE37B652T4W LE37B65H02 panel Panel T37H4040402G V.
PSU Advanced
According to the conditions of compliance with modern world standards for household switching power supplies, the BN44-00264C module provides for the use of a Power Factor Correction unit. The PFC circuit is a flyback converter based on the FAN7530 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 LE40B550A5W device:
Installed matrix (LCD panel) LTF400HA08 A03.
To power the backlight, a converter is used, combined with a power supply, controlled by the BD9893 PWM controller. The transformer 332430028EF, 332430029EF is installed in the inverter converter. As power elements of the inverter, keys of the STP9NK50ZFP type are used.
The necessary supply voltages for all nodes of the TV SAMSUNG LE40B550A5W are formed by the power module BN44-00264C, or its analogs using microchips FAN7530 (PFC), 3BR1065JF and power switches of the type STF11NM60N (PFC).
MainBoard - the main board (motherboard) is a BN41-01167B module, using SPI Flash chips: MX25L6405D and others.
Tuner TDHG6-K12A BN40-00145A provides the reception of television programs and tuning to channels.
Information from an alternative source:
Samsung LE40B550A5W chassis N68A Matrix - LTF400HA08 T-con FHD60C4L V1.1, percent THF9301, eeprom24C64WP, MAX9591, TPS65167A, I7814HS-2pcs. Main - BN94-02756D, tune TDHG6-K12A, eeprom ATMLH9362EB-1, eepromATMLH94402B-1 2 pieces, sdram K4T51163QG-HCE7 4piece, hdmi I9287CNU, stereo audio codec WM8593SEFT, ULF STA339BW PSU -.. BN44-00264C, PFC FAN7530, F11NM60N- 2pcs, SURF1060, dezh.3BR1065JF, slave.FQPF9N50C 2pcs. Inverter PWM BD9893F, LM358F Remote: BN59-00939A