Monday 16 March 2020

REPAIR / SERVICING TV SHARP LC-42SD1RU

Technical description and composition of the TV SHARP LC-42SD1RU, type of panel and applicable modules. The composition of the modules.
SHARP
Model: LC-42SD1RU
Panel: T420XW01 V.7
T-CON: T420XW01 V4
Inverter (backlight): 4H.V1838.381 / C2, 4H.V1838.371 / C2
Power Supply (PSU): DPS-263AP 193WJQZ
PWM Power: L6562 (PFC), DAS01A, DLA001 (PWM Push-pull), DAP011 (PWM Flyback), LM358
MainBoard: XD890WJN3, KD890WE18, KD890V100018,
IC MainBoard: VCT 6973G B3 000 (B3), LPM240T100G5N, DFN9M0637A (B823), SIL9023CTU, 24LC64; ;
Tuner: DUNTKD609WE, QPWBND609WJN4
Control: VCT 6973G B3 000 (B3), LPM240T100G5N, DFN9M0637A (B823), SIL9023CTU, 24LC64
Technical Specifications LC-42SD1E
SHARP LC-42SD1RU
General recommendations for repairing TV LCD
It is advisable to start diagnosing a malfunction of the SHARP LC-42SD1RU TV, like all others, with an external examination of possible changes, both external and internal elements. Visible damage to elements can sometimes suggest further directions for finding a defect before starting the necessary measurements. Ring cracks in the soldering of the leads of the heating elements, swollen electrolytic capacitors, a charred paint layer on the resistors - all this for the repairman can be a hint in the assumptions about the causes and consequences of the malfunction.
If the power supply module malfunctions, the external manifestations may be different, for example, the SHARP LC-42SD1RU does not turn on at all and there is no indication of the indicator lights on the front panel. In this case, the diagnosis and repair of the common power supply should always be started by checking the mains fuse. When it breaks, it is advisable to check for a breakdown, first of all, all power semiconductor elements of the converter and the rectifier diode bridge of the network, as well as the large electrolytic capacitor of the filter of the network rectifier and the key transistor.
In most cases, a breakdown of the N-Fet converter key does not occur for no reason and you should look for other faulty circuit elements that could provoke a defect. This can be dried electrolytic capacitors in the primary circuit, and faulty damper elements, as well as dangling resistors or punched semiconductor elements in the stabilization circuits. Possible defective PWM chip from the manufacturer.
If an active Power Factor Corrector (PFC) is used in the power module circuitry, it is sometimes more difficult to troubleshoot. Knowledge, experience, intuition and skills in such cases have a great advantage for a successful repair.
If there is no image when you turn on the SHARP LC-42SD1RU, or it appears for a second and disappears completely, but there is sound, most likely either the backlight or their power converter (inverter) are faulty. It is necessary to check the electrolytic capacitors of the filter of the secondary rectifiers in the general power supply unit.
Diagnostics of the inverter can be difficult due to the operation of the protection, which is organized by the designers to prevent negative consequences or fires in emergency cases, for example, during short circuits or breaks in the lamp power supply circuit, as well as their possible depressurization. To make the necessary measurements at control points or take the necessary waveforms, repairmen have to block the protection circuits in order to be able to diagnose.
Turning off the protection for diagnostic purposes, it must be remembered that in this case there is a risk of failure of the inverter power elements. Upon completion of the diagnosis, all regular protection circuits should be restored.
We recommend the owners of the LC-42SD1RU TV for repair only to qualified specialists with experience! Self-repair attempts without the appropriate knowledge and skills can lead to serious negative consequences!



Service manual / schematic diagram  ------------------->  
Sharp LC-42SD1E, LC-42SD1RU


 The appearance of the MainBoard XD890WJN3 is shown in the figure below:
XD890WJN3
XD890WJN3 can be used in TVs:
SHARP LC-37P70E (Panel LK370P3LZ10Z), SHARP LC-37SV1RU (Panel LK370T3LZ5BX), SHARP LC-42SD1RU (Panel T420XW01 V.7), SHARP LC-32SV1RU (Panel LK315T3LF14).
PSU Advanced
According to the conditions of compliance with modern world standards for household switching power supplies, the DPS-263AP module provides for the use of a Power Factor Correction unit. The PFC circuit is a flyback converter based on the L6562 PWM controller. The reactance of an electrolytic capacitor of a line filter at a frequency of 50-60 Hz is usually not more than 20-30 ohms and its charge directly from the network through open diodes could reach tens of amperes per pulse if no filtering were applied.
As a result of the PFC conversion, an increased voltage on the capacitor (about 380V) cannot directly open the rectifier diodes, on the anode of which the voltage will always be slightly less (about 300V) and then its charging current will always be limited by the elements of the PWM controller. As a result, the envelope of the high-frequency pulses of the consumed current will repeat the shape and phase of the input sinusoidal voltage. The presence of an increased voltage (+ 380V) on the network capacitor indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the SHARP LC-42SD1RU device:
Installed matrix (LCD panel) T420XW01 V.7.
The matrix control uses the Timing Controller (T-CON) T420XW01.
To power the backlight, an inverter 4H.V1838.381 is used.
The necessary supply voltages for all nodes of the SHARP LC-42SD1RU TV are generated by the DPS-263AP power supply module or its analogs using microcircuits L6562 (PFC), DAS01A, DLA001 (PWM Push-pull), DAP011 (PWM Flyback), LM358.
MainBoard - the main board (motherboard) is an XD890WJN3 module using VCT 6973G B3 000 (B3), LPM240T100G5N, DFN9M0637A (B823), SIL9023CTU, 24LC64 microcircuits; ; and others.
The tuner DUNTKD609WE, QPWBND609WJN4 provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: AUO
Model: T420XW01 V7
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1366x768, WXGA
Display Mode: AMVA, Normally Black, Transmissive
Active Area: 930.25x523.01 mm
Surface: Antiglare, Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 1500: 1
Display Colors: 16.7M (8-bit)
Response Time: 15/5 (Tr / Td); 6 (G to G)
Frequency: 60Hz
Lamp Type: 20 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 5.0V


 LCD TV SHARP LC-42SD1E with an LCD display, diagonal size 42 "(106 cm) in 16: 9 format. The brightness of the screen is 450 cd / m² by CCFL (EEFL) fluorescent lamps. Contrast as the ratio of maximum brightness to minimum not less than 1200: 1.
You can view images in high quality HD at a resolution of 1366x768 pixels in the standard of graphic decomposition 720p (HD Ready). The input high-frequency or video signal can be processed in analogue systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i.
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, SCART x2, RGB, VGA, HDMI, 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.
A digital tuner is capable of receiving television channels in DVB-T standards.
The power consumed by the TV from the network in operating mode is 203 watts.
Overall dimensions: with stand 1029x768x304 mm, without stand 1029x709x133 mm.
TV Weight: with stand: 33.4 kg, without stand: 29.8 kg.
Attention! The panel of the SHARP LC-42SD1E LCD TV is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!