Friday 1 May 2020

REPAIR / SERVICING TV MYSTERY MTV-4629LTA2

Technical description and composition of the MYSTERY MTV-4629LTA2 TV, panel type and applicable modules. The composition of the modules.
MYSTERY LED
Model: MTV-4629LTA2
Chassis / Version: V1M11
Panel: HV460WU2-200
T-CON: HV460WU2-200
LED driver (backlight): integrated into PSU
PWM LED driver: OB2263, AP3616M28-G1
MOSFET LED driver: MDF0765
Power Supply (PSU): TV4205-ZC02-01
PWM Power: FAN7930 (PFC), OB2273
MainBoard: MSAV3220-ZC26-02 (B) P / N: 303C3220156
IC MainBoard: CPU: MSD308BT-SW, SPI Flash: GD25Q64B, EEPROM T-con 24C16, Scaller: NT71263FG-300
Tuner: JX
Technical Specifications MTV-4629LTA2
MYSTERY MTV-4629LTA2
General repair guidelines for TV LCD LED
Possible malfunctions
- The MYSTERY MTV-4629LTA2 TV does not turn on, does not respond to the remote control and the control panel buttons, the indicators do not light or flash.
Typically, with such manifestations, the defect is caused by faulty elements in the TV4205-ZC02-01 power module. It is necessary to measure the secondary output voltage, and in case of their absence, check the serviceability of the power switches of the converters and rectifier diodes for a short circuit.
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.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, power supply, frequency-setting, damper ... as well as elements of the Negative Stabilization Feedback. PWM chip FAN7930 (PFC), OB2273 can also cause a malfunction of the power switch of the converter and is checked by replacement.
- 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.
Often in such cases, there is no LED backlight. The reason can be both in the power supply of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
It is impossible to detect a break in the LED line without disassembling the panel with a simple multimeter. The LEDs are connected in series and to open their transitions, a voltage of several tens of volts is required. Ideally, a current source is suitable for such purposes. You can open the panel and check each LED separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect the probes in the forward direction to it (red probe to the anode, black to the cathode). 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 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 MSAV3220-ZC26-02 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). When repairing an MB board, you need to check its CPU components: MSD308BT-SW, SPI Flash: GD25Q64B, EEPROM T-con 24C16, Scaller: NT71263FG-300. Defective items should be replaced. If chips with BGA soldering technology are used, a problem in its implementation is detected by the local heating of the chip.
In the absence of tuning to the channels of on-air or cable television, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltages at the terminals of the JX tuner. It is also necessary to check the presence of pulses of data exchange between the tuner and the processor via the I2C bus using an oscilloscope.
Owners and users of the MYSTERY MTV-4629LTA2 TV should remember that self-repair without special knowledge, skills and qualifications can be fraught with negative consequences that can lead to complete non-repairability of the device!

SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    TV4205-ZC02-01 Schematic diagram

 The appearance of the MainBoard MSAV3220-ZC26-02 (B) is shown in the figure below:
To reduce the backlight current in LED drivers with the AP3616M28-G1 terminal stage, the total resistance of the resistors from terminal 22 (ISET AP3616M28) to the housing should be proportionally increased. The maximum current in each of the 16 channels is 75 mA. To increase the current in the diodes, the channels are connected in parallel. The current in milliamperes in each channel is determined from the calculation of 1560 * 1.194 / Rset, where Rset is the resistance from the ISET output to the housing in kilo-ohms.

MSAV3220-ZC26-02
MSAV3220-ZC26-02 can be used in TVs:
BBK LEM3284DT2 (Panel LSC320AN02), MYSTERY MTV-2224LT2 (Panel CLAA215FA10), MYSTERY MTV-4028LTA2 (Panel V390HJ1-P02), MYSTERY MTV-4829LTA2 (Panel LSC480HN02-G), MYSTERY MTV-4129LT2 (Panel LK400D3HC34K), MYSTERY MTV-2424LT2 (Panel HM236WU8-200 ), MYSTERY MTV-4030LT2 (Panel V400HJ6-PE1), MYSTERY MTV-4629LTA2 (Panel HV460WU2-200).
The appearance of the power supply
Main features of the MYSTERY MTV-4629LTA2 device:
Installed matrix (LED-panel) HV460WU2-200.
The matrix control uses the Timing Controller (T-CON) HV460WU2-200.
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by the OB2263 PWM controller, AP3616M28-G1. As power elements of the LED driver, keys of the MDF0765 type are used.
The necessary supply voltages for all nodes of the MYSTERY MTV-4629LTA2 television are generated by the TV4205-ZC02-01 power supply module or its analogs using FAN7930 (PFC), OB2273 microcircuits.
MainBoard - the main board (motherboard) is an MSAV3220-ZC26-02 module, using CPU chips: MSD308BT-SW, SPI Flash: GD25Q64B, EEPROM T-con 24C16, Scaller: NT71263FG-300 and others.
The JX tuner provides television reception and channel tuning.
MYSTERY MTV-4629LTA2 TV with HV460WU2-200 LCD, 46 "(117 cm) diagonal size in 16: 9 format. The required screen brightness of 350 cd / m² is provided by LED backlighting. Contrast, as the ratio of maximum brightness to minimum, is 2000: 1. Edge LED backlighting is implemented in the LED-panel of this TV - Edge LED.The design and technical capabilities of the TV include viewing programs and movies in high quality HD at a resolution of 1920x1080 pixels in a graphic resolution according to the standard 1080p (Full HD). the 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, 1080p. Supported media file formats: MP3, MPEG4, DivX, JPEG .
The power of the sound system 20 W (2x10 W) provides two speakers. The audio processing system NICAM STEREO is used.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, VGA, HDMI x2, USB, Ethernet (RJ-45), Wi-Fi. 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, 1360x768, 1920x1080.
A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Dimensions: With stand 642x444x209 mm, Without stand 570x345x70 mm.
Attention! The HV460WU2-200 panel of the MYSTERY MTV-4629LTA2 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.