Technical description and composition of the SHARP LC-20SH2E TV, type of panel and applicable modules. The composition of the modules.SHARP
Model: LC-20SH2E
Panel: LQ197V3GZ83
Inverter (backlight): Q574735004371B.L
Power Supply (PSU): QPWBFD283WJN2 / DUNTKD283WE
PWM Power: STR-W67652E
MainBoard: Q5737DS002976
IC MainBoard: TDA15521E / N1B80, BD8120FP, IXA370WJ, 24C64, 39VF010
Tuner: 1736DS059918
Technical Specifications LC-20SH2E
SHARP LC-20SH2E
General recommendations for repairing TV LCD
Possible manifestations of defects
- The SHARP LC-20SH2E TV does not turn on and does not show any signs of operability at all. There is no reaction to the remote control and control buttons from the front panel.
Failure in such cases should begin to be sought in the power supply circuits QPWBFD283WJN2. It is necessary to measure its secondary output voltages, and if they are absent, check the power switches and rectifier diodes in the converters for a short circuit.
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 main fuse and, less often, the current sensor at the source of the key are most often cut off.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, in the power supply circuit of a PWM controller, in frequency-setting or damping circuits, as well as in Negative Stabilization Feedback. PWM chips STR-W67652E are usually checked by replacing with new, or obviously working.
- There is no image, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
The defect can be caused by problems in the nodes or elements of the backlight of the display, or in the power supply of the lamps or the inverter.After checking all the electrolytic capacitors of the filters that are involved in the power supply to the inverter, you must ring in its converter power keys for breakdown and secondary windings of transformers for an open.
Sometimes, for diagnostic purposes, inverter protection must be disabled. In such cases, special care must be taken during work, and the protection circuits should be restored immediately after the repair is completed.
- 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 Q5737DS002976 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). Sophisticated MB board repair (SSB) is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the elements TDA15521E / N1B80, BD8120FP, IXA370WJ, 24C64, 39VF010. BGA chip malfunctions are usually easy to detect by warming up.
If the TV works normally from external devices, but does not tune into television channels, tuner 1736DS059918 may be malfunctioning. In such cases, first of all, you should make sure that there are supply voltages at its corresponding conclusions. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the cause of the inoperability of the tuner may be a software failure.
Once again, we remind TV users: you should not make attempts to repair it yourself without the appropriate knowledge, experience and the necessary qualifications! Entrust repair to professionals with sufficient experience in the field of repair of electronic equipment.
Service manual / schematic diagram ------------> SHARP LC-20SH2E Chassis
Main features of the SHARP LC-20SH2E device:Installed matrix (LCD panel) LQ197V3GZ83.
To power the backlight used inverter Q574735004371B.L.
The necessary supply voltages for all nodes of the SHARP LC-20SH2E TV are generated by the QPWBFD283WJN2 power module or its analogs using STR-W67652E microcircuits.
MainBoard - the main board (motherboard) is a Q5737DS002976 module, using TDA15521E / N1B80, BD8120FP, IXA370WJ, 24C64, 39VF010 and other chips.
The tuner 1736DS059918 provides the reception of television programs and tuning to channels.