Monday 16 March 2020

REPAIR / SERVICING TV SHARP LC-42SH7

Technical description and composition of the SHARP LC-42SH7 TV, panel type and applicable modules. The composition of the modules.
SHARP
Model: LC-42SH7 LC-42SH7RU-BK
Chassis / Version: 715G3535-3
Panel: V420H1-L15 Rev. C1
Lamp backlight: 12 Lamp CCFL
T-CON: V420H1-C15
Inverter (backlight): VIT70079.10 REV: 1
Power Supply (PSU): 715G3662-P01-H20-003U
PWM Power: L6599D, SG6961, TNY277 (Stb)
MOSFET Power: 2SK4086, 2SK4097LS
MainBoard: 715G3535-3
IC MainBoard: CPU: MT5362ANG, Eeprom: 24C32WP, SPI Flash: MX25L4005, NAND Flash: NAND128W3A2BN6
Tuner: FQD1116ME / BM-TPV
Control: IR: 715G3542-1
Technical Specifications LC-42SH7
SHARP LC-42SH7
General recommendations for repairing TV LCD
Possible manifestations of defects
- The SHARP LC-42SH7 TV does not turn on at all. The control lights do not light or flash. The TV on the remote control and the control panel buttons do not respond.
In such cases, the 715G3662-P01-H20-003U power supply is usually faulty. Then we recommend that you measure its output voltages and, if they are absent, you should check the health of the power switches (2SK4086, 2SK4097LS) and rectifier diodes of the converters for possible short circuit.
In case of any breakdowns in the secondary circuits, the converter can operate in emergency short-circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key more often breaks.
Mos-Fet power switches, used in switching power supplies, sometimes fail due to a malfunction of any other elements that can put it out of operation in key mode or create an excess of the maximum permissible parameters of the switch. These can be elements supplying the PWM controller, frequency-setting or damping circuits, or negative feedback elements in the stabilization circuit. PWM controllers L6599D, SG6961, TNY277 (Stb), in the absence of visible damage or obvious short-circuit between the terminals, are checked by replacing with new, or obviously working.
- There is no image, there is sound, it is responding to the remote control. Or immediately after turning on for a second, the image may appear and immediately disappear.
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. If all the electrolytic capacitors of the filter for the power supply of the inverter are working, you should make sure the lamps are working, then you need to check the converter keys and the secondary windings of the transformers.
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 when working, and after they are finished, it is necessary to restore the protection circuits for further safe operation of the TV by the owner in normal mode.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the 715G3535-3 motherboard should begin by checking the stabilizers and power converters needed to power the microcircuit and matrix. If necessary, update or replace the software (software). In cases of complex repairs of MB (SSB) and with the necessary skills and equipment, sometimes it may be necessary to replace its CPU chips: MT5362ANG, Eeprom: 24C32WP, SPI Flash: MX25L4005, NAND Flash: NAND128W3A2BN6 and other possible malfunctioning components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
Before replacing the FQD1116ME / BM-TPV tuner, if there is no tuning for the channels, you must first check the software and the supply voltage at its terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus
Attention to users! Self-repair of a TV SHARP LC-42SH7 without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!

Service Manual with Schematic Diagram 213 pages of 2008 on models LC-19SH7E, LC-26SH7E, LC-32SH7E, LC-42SH7E, LC-19SH7RU, LC-26SH7RU, LC-32SH7RU, LC-42SH7RU

Service manual / schematic diagram  ------------------->   SHARP LC-42SH7 Chassis 715G3535-3

PSU  / schematic diagram  ------------------->  
715G3662 Power supply

 The appearance of the MainBoard 715G3535-3 is shown in the figure below:
715G3535-3
Main features of the SHARP LC-42SH7 device:
Installed matrix (LCD panel) V420H1-L15 Rev. C1.
The matrix control uses the Timing Controller (T-CON) V420H1-C15.
To power the backlight used inverter VIT70079.10.
The necessary supply voltages for all nodes of the SHARP LC-42SH7 television are generated by the power supply module 715G3662-P01-H20-003U, or its analogs using microchips L6599D, SG6961, TNY277 (Stb) and power switches of the type 2SK4086, 2SK4097LS.
MainBoard - the main board (motherboard) is a 715G3535-3 module, using CPU chips: MT5362ANG, Eeprom: 24C32WP, SPI Flash: MX25L4005, NAND Flash: NAND128W3A2BN6 and others.
The FQD1116ME / BM-TPV tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: CMO
Model: V420H1-L15
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: Super MVA, Normally Black, Transmissive
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 11%)
Brightness: 500 cd / m²
Contrast Ratio: 4000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 6.5 (G to G)
Frequency: 60Hz
Lamp Type: 12 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V

 SHARP LC-42SH7 LCD TV with V420H1-L15 LCD, 42 "(107 cm) diagonal display in 16: 9 aspect ratio.
The design and technical capabilities of the TV include watching programs and movies in high quality HD at a resolution of 1920x1080 pixels in a graphical decomposition according to the standard 1080p (Full HD). The input high-frequency or video signal can be processed in analogue systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p.
The power of the sound system 20 W (2x10 W) provides two speakers. It uses a NICAM stereo signal processing system and Sound Surround.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x3, S-Video, component, SCART x2, RGB, VGA, HDMI x3, USB, RS-232. An output for connecting headphones is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is used on the TV case, this interface supports resolutions: 640x480, 800x600, 1024x768, 1280x1024, 1360x768, 1920x1080.
The digital tuner is capable of receiving television channels in DVB-T MPEG4 standards.
The power consumed by the TV from the network in operating mode is 153 watts.
Overall dimensions: with stand 1015x706x270 mm, without stand 1015x655x112 mm.
TV mass: with stand: 19.1 kg, without stand: 16.5 kg.
Attention! Panel V420H1-L15 Rev. The C1 LCD TV SHARP LC-42SH7 is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!