Friday, 27 December 2019

REPAIRING / SERVICING TV SAMSUNG LE40A558P3F

Technical description and composition of the SAMSUNG LE40A558P3F TV, panel type and applicable modules. The composition of the modules.
SAMSUNG
Model: LE40A558P3F LE40A558
Chassis / Version: GPR40SEN
Panel: LTF400HA03
T-CON: FHD60C4LV0.3
Inverter (backlight): integrated into PSU
PWM Inverter: LX1692BIDW
MOSFET Inverter: 2SK3561
Trans Inverter: EER2940
Power Supply (PSU): BN44-00199A IP-211135A
PWM Power: AN7530, STM4472, FSQ0765RG, LX1692BIDW, 74VHC123A
MOSFET Power: FCPF11N60
MainBoard: BN41-00974B
IC MainBoard: MT8226, MT8291E, NTP-3100, WT61P8, SDP72, D61211GM, HYB25DC256163CE-4, K4T56163QT, TMDS351
Tuner: BN40-00120A TDHG6-K10A
Control: IR: BN41-00990A REV: V0.6
Technical Specifications LE40A558P3F
SAMSUNG LE40A558P3F
General repair guidelines for TV LCD
Possible manifestations of defects
- SAMSUNG LE40A558P3F TV does not turn on, does not respond to the remote control and control panel buttons, indicators do not light up and do not blink.
In such cases, the fault should be sought first in the BN44-00199A power supply module. In the absence of the necessary supply voltages in the secondary circuits of the converters, it is necessary to check the power switches (FCPF11N60) and rectifier diodes for a possible partial or complete breakdown.
In case of breakdowns of semiconductors in the secondary circuits of any converter, as a rule, it can operate in emergency short-circuit mode without output voltages, and during short circuit in the elements of the primary circuit, the mains fuse and, less often, the current sensor at the source of the key are most often cut off.
The breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in the circuits supplying the PWM controller, frequency-setting or damper ones, as well as in the circuits of Negative Feedback (OOS) stabilization. PWM controllers (PWM) AN7530, STM4472, FSQ0765RG, LX1692BIDW, 74VHC123A, if they do not have visible damage to the case and open fault between the terminals, are usually checked by replacement.
- 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.
These manifestations can be triggered by a power supply module, or by inverter defects, as well as a distortion of the currents in the lamps due to their uneven wear. After checking all the electrolytic capacitors of the filters that are involved in powering the inverter, you should ring in its converter power keys for breakdown and the 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 BN41-00974B 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 MT8226, MT8291E, NTP-3100, WT61P8, SDP72, D61211GM, HYB25DC256163CE-4, K4T56163QT, TMDS351 and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
In the absence of tuning to the channels of on-air or cable television, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltage at the terminals of the tuner BN40-00120A TDHG6-K10A. It is also necessary to check, using an oscilloscope, the presence of pulses of data exchange between the tuner and the processor via the I2C bus.
Once again, we remind TV users: you should not make attempts to repair it yourself without the appropriate knowledge, experience and the necessary qualifications! Trust the repair to professionals with sufficient experience in the repair of electronic equipment.

Service manual and schematic diagram ----->  SAMSUNG LE40A558P3F Chassis GPR40SEN.

PSU SCHEMATIC  Samsung ------> BN44-00199A Power supply.

LE40A558P3C - Panel: T400HW01 V.4, T-CON: T400HW01 V4 CTRL BD 40T02-C02, Invertor: 4H.V2358.181/D, MainBoard: BN41-00974B, PSU: BN44-00199A



MainBoard BN41-00974B view 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 LE40A558P3F device:
Installed matrix (LCD panel) LTF400HA03.
The matrix control uses the Timing Controller (T-CON) FHD60C4LV0.3.
To power the backlight, a converter is used, combined with the power supply, controlled by the LX1692BIDW PWM controller. The transformer EER2940 is installed in the inverter converter. As power elements of the inverter, keys of type 2SK3561 are used.
The necessary supply voltages for all nodes of the SAMSUNG LE40A558P3F TV are generated by the BN44-00199A power supply module or its analogs using AN7530, STM4472, FSQ0765RG, LX1692BIDW, 74VHC123A microcircuits and power switches of the FCPF11N60 type.
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 TDHG6-K10A provides the reception of television programs and tuning to channels.