Thursday 12 March 2020

REPAIR / SERVICING TV SHARP LC-40LE814E

Technical description and composition of the TV SHARP LC-40LE814E, type of panel and applicable modules. The composition of the modules.
SHARP LED
Model: LC-40LE814E
Panel: LK400D3LWF2Y
T-CON: RUNTKCPWBX 4512TP
LED driver (backlight): integrated into PSU
PWM LED driver: DDA003A, DDA002B
MOSFET LED driver: 2N7002LT1G
Power Supply (PSU): DPS-126CP
PWM Power: NCP1608BDR2G (PFC), ICE3BS03LJG (PWM 8pin), DDA002C
MOSFET Power: SPA11N60C3 (PFC), 2SK4013, FQPF10N60C
MainBoard: QPWBXF455WJZZ DKEYDF455FM11
IC MainBoard: Mediatek MT5391DWCJ
Tuner: RTUDAA053WJQZ
Technical Specifications LC-40LE814
SHARP LC-40LE814E
General repair guidelines for TV LCD LED
Possible malfunctions
- SHARP LC-40LE814E does not turn on, the indicators on the front panel do not light or flash. The TV does not respond to the control buttons and the remote control.
Often in such cases, the DPS-126CP power module is faulty. It is necessary to measure its output supply voltages, and in case of their absence, check the serviceability of the power switches of the converters and rectifier diodes for the probability of breakdown in PN semiconductor junctions.
In the event of a breakdown in the secondary circuits of the converter, it can usually fail in short circuit mode, and in the event of a short circuit in the power elements of the primary circuit, the mains fuse or current sensor at the source of the key most often breaks.
Breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback circuits (OOS) of stabilization. PWM controllers (PWM) IC_Power, 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, there is sound, it responds to the remote control, the channels are switched. In some cases, the image appears when you turn on and immediately disappears.
In such cases, the most likely malfunction of the LED backlight elements. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It is impossible to check the LED line for breaks without disassembling the panel with a multimeter or tester. For these purposes, it is necessary to open all series-connected PN junctions and a voltage of the order of tens of volts will be required, and ideally, a current source. Having disassembled the panel, it is necessary to check each LED separately. Chinese multimeters, as a rule, light up a single 3-volt LED in the forward direction. In the case of using dual 6-volt LEDs, the PN junction of its protective zener diode can serve as a health indicator. In faulty LEDs, the zener diode will either be cut off or broken into short-circuit.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the QPWBXF455WJZZ motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). Board repair and replacement of Mediatek MT5391DWCJ microcircuits are carried out with the necessary equipment, and the corresponding element base. Faults associated with the application of BGA processor soldering technologies can be localized by the heating method.
Tuner malfunction Tuner is installed after checking the software and all the supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
It should be remembered! Attempts to self-repair the SHARP LC-40LE814E TV, 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!


Service manual / schematic diagram ------------------>  SHARP LC-40LE814E, LC-40LE814RU, LC-46LE814E, LC-46LE814RU, LC-40LE824E, LC-40LE824RU, LC-46LE824E, LC-46LE824RU

models:   LC-40LE814E, LC-40LE814RU, LC-46LE814E, LC-46LE814RU, LC-40LE824E, LC-40LE824RU, LC-46LE824E, LC-46LE824RU


 The appearance of the MainBoard QPWBXF455WJZZ is shown in the figure below:
QPWBXF455WJZZ
QPWBXF455WJZZ can be used in TVs:
SHARP LC-40LE814E (Panel LK400D3LWF2Y), SHARP LC-40LE810E LC-40LE810ERU (Panel LK400D3LWF2Y).
The appearance of the power supply
Main features of the SHARP LC-40LE814E device:
Installed matrix (LED-panel) LK400D3LWF2Y.
The matrix control uses the Timing Controller (T-CON) RUNTKCPWBX.
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by a PWM controller DDA003A, DDA002B. As power elements of the LED driver, keys of the 2N7002LT1G type are used.
The necessary supply voltages for all nodes of the SHARP LC-40LE814E TV are generated by the DPS-126CP power supply module or its analogs using NCP1608BDR2G (PFC), ICE3BS03LJG (PWM 8pin), DDA002C microcircuits, and power switches of the type SPA11N60C3 (PFC), 2SKPF103, 2SKPF013.
MainBoard - the main board (motherboard) is a QPWBXF455WJZZ module, using Mediatek MT5391DWCJ chips and others.
The tuner RTUDAA053WJQZ provides reception of television programs and tuning to channels.