Friday, 27 December 2019

REPAIRING / SERVICING TV SAMSUNG LE37A552

Technical description and composition of the SAMSUNG LE37A552 TV, type of panel and applicable modules. The composition of the modules.
SAMSUNG
Model: LE37A552 LE37A552P3R
Chassis / Version: GPR37SEN
Panel: T370HW02 V.4
T-CON: T370HW02 V402
Inverter (backlight): VIT71037.50
PWM Inverter: OZ964SN
MOSFET Inverter: APM4052D
Power Supply (PSU): BN44-00216A PSLF231501C
PWM Power: MC33067P (16), FAN7530 (PFC), FSQ0365RN
MOSFET Power: 17N60 (PFC), 9N50 (PWM)
MainBoard: BN41-00974B MT8226
IC MainBoard: MT8226, MT8291E, NTP-3100, WT61P8, SDP72, D61211GM, HYB25DC256163CE-4, K4T56163QT, TMDS351
Tuner: BN40-00120A
Technical Specifications LE37A552P3R
SAMSUNG LE37A552
General repair guidelines for TV LCD
It is advisable to start the diagnostics of a malfunction of the SAMSUNG LE37A552 TV, like all others, with an external examination of both external and internal elements. Specific external damage can sometimes prompt further actions to determine the malfunction of the TV and the localization of the defect before the necessary measurements and waveforms are taken. In most cases, the repairman can guess the causes of the defect and possible consequences by the characteristic signs of typical TV defects, for example, ring cracks formed in the soldering of element outputs, swollen rectifier filter capacitors, charred resistors and other circuit elements.
If the SAMSUNG LE37A552 does not turn on, no control lights on the front panel light up or blink, therefore, there is a very high probability of a power module malfunction. When diagnosing and repairing the power supply, it is necessary first of all to check the fuse, and if it breaks, you should check the power switch and rectifier bridge diodes for avalanche (thermal) breakdown.
It should be remembered that the N-FET keys used in flyback converters rarely fail for no reason to be looked for by checking other elements of the circuit. Often the breakdown is caused by malfunctions of electrolytic capacitors or semiconductor elements in the primary circuit, or by a break in the resistors in the stabilization circuits. The PWM controller chip PSLF231501C can also cause a breakdown of the power switch of the converter.
In cases where the Power Factor Corrector (PFC) is used in the power supply, troubleshooting can be a bit more complicated.
If the SAMSUNG LE37A552 TV does not have an image, but there is sound, the malfunction should be sought in the power converter of the backlight (inverter). It is also necessary to check the serviceability of the electrolytic capacitors of the filter of the secondary rectifiers of the BP (power supply) for an overstated ESR.
The operation of the power circuits of the inverter and the backlight in the normal mode are controlled by special protection, which is organized for fire safety, for example, to disconnect during short circuits or breaks in high-voltage connections or during depressurization of lamps. This protection makes it difficult to diagnose and repair the inverter.
In such cases, the risk of failure of the power elements of the inverter is most likely, and special care is required during operations, and after their completion, it is necessary to restore the protection circuit for further safe operation of the TV by the owner in normal mode.
On the motherboard MT8226, in the event of a malfunction, you should first check the performance of all the power regulators of the microcircuits and, if necessary, update the software (software).
It should be remembered! Attempts to repair the TV SAMSUNG LE37A552, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!

SCHEMATICS ----->  Samsung LE32A55*P, LE37A55*P, LE40A55*P, LE46A55*P, LE52A55*P Chassis GPR32SEN, GPR37SEN, GPR40SEN, GPR46SEN, GPR52SEN.

The appearance of the MainBoard BN41-00974B is shown in the figure below:

BN41-00974B
BN41-00974B can be used in TVs:
SAMSUNG LE32A556P1 LE32A556P1F (Panel LTF320HA01 A04), SAMSUNG LE37A552 LE37A552P3R (Panel T370HW02 V.4), SAMSUNG LE37A656A1 LE37A656A1FXRU (Panel T370HW02 V6), SAMSUNG LE32A558P3F (Panel LTF320HA01), SAMSUNG LE40A656A1F (Panel LTF400HC01 A02), SAMSUNG LE37A615A3F LE37A615 (Panel T370HW02 V.4), SAMSUNG LE40A556P1F (Panel V400H1-L03 REV C1), SAMSUNG LE40A558P3F LE40A558 (Panel LTF400HA03), SAMSUNG LE32A656A1F (Panel LTF320HA04).
The appearance of the power supply
Main features of the SAMSUNG LE37A552 device:
Installed matrix (LCD panel) T370HW02 V.4.
The matrix control uses the Timing Controller (T-CON) T370HW02.
The VIT71037.50 inverter is used to power the backlight lamps, it is controlled by the OZ964SN PWM controller. As power elements of the inverter, keys of the APM4052D type are used.
The necessary supply voltages for all nodes of the SAMSUNG LE37A552 TV are generated by the BN44-00216A power module or its analogs using microcircuits MC33067P (16), FAN7530 (PFC), FSQ0365RN and power switches of the type 17N60 (PFC), 9N50 (PWM).
MainBoard - the main board (motherboard) is a BN41-00974B module, using microcircuits MT8226, MT8291E, NTP-3100, WT61P8, SDP72, D61211GM, HYB25DC256163CE-4, K4T56163QT, TMDS351 and others.
The tuner BN40-00120A provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: AUO
Model: T370HW02 V4
Type: a-Si TFT-LCD, Panel
Diagonal size: 37 inch
Resolution: 1920x1080, FHD
Display Mode: AMVA, Normally Black, Transmissive
Active Area: 819.36x460.89 mm
Surface: Antiglare (Haze 11%), Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 2500: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 6.5 (G to G)
Frequency: 60Hz
Lamp Type: CCFL Embedded (Inverter)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V