Saturday 11 April 2020

REPAIR / SERVICING TV DAEWOO L32S639VKE

Technical description and composition of the DAEWOO L32S639VKE TV, panel type and applicable modules. The composition of the modules.
DAEWOO LED
Model: L32S639VKE
Chassis / Version: MSD3463-T4C1
Panel: LC320DXY (SJ) (A7) // K320WD82
T-CON: 6870C-0442B
LED driver (backlight): integrated into MainBoard
PWM LED driver: OB3350CP
MOSFET LED driver: AOD4286
Power Supply (PSU): integrated into MainBoard
PWM Power: LNK6777
MainBoard: MSD3463-T4C1
IC MainBoard: SPI Flash: MX25L6406E, Audio: TPA3110LD2
Tuner: ST43WS-2A-E
Technical Specifications L32S639VKE
DAEWOO L32S639VKE
General repair guidelines for TV LCD LED
Possible malfunctions
- DAEWOO L32S639VKE TV does not turn on at all. There is no reaction to the remote control and control buttons from the front panel. Indicator lights do not light or flash.
In this case, first of all, you should check the operability of the main power source - AC / DC network voltage converter, all of whose elements are located on the MainBoard MSD3463-T4C1 board. In the absence of the necessary supply voltages in the secondary circuits of the converters, it is necessary to check the power switches and rectifier diodes for a possible partial or complete breakdown.
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.
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 LNK6777 are usually checked by replacing with new, or obviously working.
- 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.
The most likely in these cases is a malfunction of the LED backlight. Often the cause of the malfunction is the lack of current in the LED circuit, for example, an open or short circuit, or a violation of the contact connections of the connectors.
To check the health in the LED circuit, it is better to use a current source with a maximum voltage of 200V. We do not recommend using any voltage sources for this purpose. You can check each LED individually with a simple Chinese multimeter (powered by 9 volts) in the P-N-junction test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black to its cathode, then the 3-volt LED will light up slightly, and in the opposite direction you can detect the transition of the emergency zener diode. A zener diode PN junction indirectly indicates a LED-a
- The TV does not enter the operating mode, does not respond to the remote control. The indicator on the front panel lights constantly or blinks.
Repair or diagnostics of the motherboard MSD3463-T4C1 should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, 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 SPI Flash chips: MX25L6406E, Audio: TPA3110LD2 and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
The malfunction of the ST43WS-2A-E tuner is established after checking the software and all supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
TV users and owners need to remember that attempts to self-repair a DAEWOO L32S639VKE TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!


SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    MSD3463-T4C1 Power supply & LED-Driver
 Main features of the DAEWOO L32S639VKE device:
Installed matrix (LED-panel) LC320DXY (SJ) (A7) or K320WD82.
The matrix control uses the Timing Controller (T-CON) 6870C-0442B.
To power the backlight LEDs, a converter is used, combined with the main board MSD3463-T4C1, controlled by the OB3350CP PWM controller. As power elements of the LED driver, keys of the AOD4286 type are used.
The power module is combined with the MainBoard and is made according to the flyback AC / DC voltage converter circuit using LNK6777 microcircuits.
MainBoard - the main board (motherboard) is an MSD3463-T4C1 module using SPI Flash chips: MX25L6406E, Audio: TPA3110LD2 and others.
The ST43WS-2A-E tuner provides TV reception and channel tuning.


 Brand: DAEWOO, Model: L32S639VKE.
Briefly from the TV: LCD, LED backlight, 31.5 ", 1366x768, 720p HD HDMI: 2.
Manufacturer: HORIZON plant, Belarus, Minsk, st. S. Kovalevskoy, 62. Developer: Dongbu Daewoo Electronics Corporation.
The composition uses MainBoard MSD3463-T4C1 and LCD-panel LC320DXY (SJ) (A7). The power supply is combined with the MainBoard.

Technical description
DAEWOO LED TV L32S639VKE with LCD LC320DXY, diagonal size 31.5 "(80 cm) in 16: 9 format. The required brightness of the screen is 240 cd / m² LED backlight LED. Dynamic contrast ratio of 5,000,000: 1 is achieved by special control of the LEDs. V LCD panels are equipped with Direct LED backlighting and high-quality HD viewing at 1366x768 pixels in 720p (HD Ready) graphic standard. Supported media file formats: MP3, MPEG4, MKV, JPEG. Stereo audio is realized with two built-in and speakers, using the NICAM STEREO audio processing system.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, HDMI x2, USB. A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-T2 standards.
Overall dimensions: without stand 730x430x71 mm.
Attention! The LC320DXY (SJ) (A7) panel of a DAEWOO L32S639VKE LED TV is an expensive and unreliable element.
Avoid any impact on the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also unsafe to get liquid on the screen. Sometimes one drop is enough if it flows down the glass onto the cables so that the TV becomes unrepairable.