Saturday 11 April 2020

REPAIR / SERVICING TV DAEWOO L24V638VAE

Technical description and composition of the DAEWOO L24V638VAE TV, panel type and applicable modules. The composition of the modules.
DAEWOO LED
Model: L24V638VAE
Chassis / Version: TP.MS3663S.PA671
Panel: HV236WHB-N41
LED backlight: CY-240D-2X5 PB04D397103BL041-001H
T-CON: 47-6001451
LED driver (backlight): integrated into MainBoard
PWM LED driver: OB3350CP
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MOSFET Power: TO-252
MainBoard: TP.MS3663S.PA671
IC MainBoard: CPU: MSD3663LSA-Z1, SPI FLASH MX25L6436F, AUDIO: YD1517P
Tuner: CDT-9NT372-RF01
Technical Specifications L24V638VAE
DAEWOO L24V638VAE
General repair guidelines for TV LCD LED
Possible malfunctions
- The DAEWOO L24V638VAE TV does not turn on, does not respond to the remote control and the control panel buttons, does not light up or blink indicators.
In this case, the main power source - the AC / DC voltage converter, the elements of which in this model are located on the MainBoard TP.MS3663S.PA671 general board, may turn out to be faulty. It is necessary to measure its output voltages and, in case of their absence, check the serviceability of power switches (TO-252) and rectifier diodes in the converters for possible breakdown.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during a short circuit in the elements of the primary circuit, the mains fuse usually 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 SOT23-6 PWM controllers, in the absence of visible damage or obvious short-circuit between the terminals, are checked by replacing with new ones, or obviously working.
- There is no image, but there is sound and all other functions work. Sometimes when you turn on the image for a second appears and disappears.
In some of these cases, the malfunction is caused by a lack of backlighting on the display. Usually the cause of the malfunction is in the breakage of the LEDs, or in the connectors of the LED strips, but sometimes the LED driver also turns out to be faulty.
When diagnosing, it is necessary to take into account that it is impossible to check the open in the chain of LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally, a current source. By opening the panel, each LED can be checked separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect probes in the forward direction to it. In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of health. In the event of a LED malfunction, its 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 TP.MS3663S.PA671 motherboard should begin by checking the stabilizers and power converters needed to power the microcircuits and matrix. If necessary, update or replace the software (software). Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Checking or replacing CPU elements: MSD3663LSA-Z1, SPI FLASH MX25L6436F, AUDIO: YD1517P requires the necessary training and professional skills to repair modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by warming up.
Before replacing the tuner CDT-9NT372-RF01, 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
It should be remembered! Attempts to independently repair the DAEWOO L24V638VAE 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!



Repair MainBoard
The appearance of MainBoard TP.MS3663S.PA671 is shown in the figure below:
TP.MS3663S.PA671
Main features of the device DAEWOO L24V638VAE:
Installed matrix (LED-panel) HV236WHB-N41.
The matrix control uses the Timing Controller (T-CON) 47-6001451.
To power the backlight LEDs, a converter is used, combined with the TP.MS3663S.PA671 main board, controlled by the OB3350CP PWM controller.
The power module is combined with the MainBoard and is made according to the flyback AC / DC voltage converter circuit using PWM SOT23-6 microcircuits and TO-252 type power switches.
MainBoard - the main board (motherboard) is a TP.MS3663S.PA671 module, using CPU chips: MSD3663LSA-Z1, SPI FLASH MX25L6436F, AUDIO: YD1517P and others.
The tuner CDT-9NT372-RF01 provides the reception of television programs and tuning to channels.

Brand: DAEWOO, Model: L24V638VAE.
Shortly from the TV: LCD, 720p HD, diagonal 24 "(61 cm), there is HDMI, there is USB, there is support for DVB-T2.
Manufacturer: HORIZON plant, Belarus, Minsk, st. S. Kovalevskoy, 62. Developer: Dongbu Daewoo Electronics Corporation.

The composition uses MainBoard TP.MS3663S.PA671 and LCD-panel HV236WHB-N41. The power supply is combined with the MainBoard.



DAEWOO L24V638VAE LED TV with a 24 "(61 cm) diagonal LCD display in 16: 9 format. The required screen brightness of 180 cd / m² is provided by LED backlight LED. The ratio of maximum brightness to minimum (contrast) is 1000: 1. LED display technology is implemented in the model’s display technology and high-quality HD images can be viewed at 1366x768 pixels in 720p (HD Ready) graphic decomposition standard. Supported media file formats: MP3, MPEG4, DivX, MKV, JPEG.
The power of the acoustic system of sound 6 W (2x3 W) provide 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), audio x2, component, HDMI, USB. An output for connecting headphones is provided. A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.

Overall dimensions: with a support of 550x367x173 mm, without a support of 550x335x63 mm.

Mass of the TV: 2.4 kg.

Attention! The panel of the DAEWOO L24V638VAE 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.