Wednesday, 29 April 2020

REPAIR / SERVICING TV MYSTERY MTV-2424LT2

Technical description and composition of the MYSTERY MTV-2424LT2 TV, type of panel and applicable modules. The composition of the modules.
MYSTERY LED
Model: MTV-2424LT2
Chassis / Version: V2N02
Panel: HM236WU8-200
T-CON: HM236WU1-100 X0.0
LED driver (backlight): integrated into MainBoard
PWM LED driver: AP3039AM-G1, AP3608EM
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MainBoard: MSDV3222-ZC01-01 & MSAV3220-ZC26-02 (B) (P / N: 303C3220156)
IC MainBoard: CPU: MSD308BT-SW, SPI Flash: GD25Q64B, EEPROM T-con 24C16, Scaller: NT71263FG-300
Control: IR: TV2461-ZC25-01 (A)
Technical Specifications MTV-2424LT2
MYSTERY MTV-2424LT2
General repair guidelines for TV LCD LED
Possible malfunctions
- The MYSTERY MTV-2424LT2 TV does not turn on at all. The control lights do not light or flash. On the remote control and the buttons on the control panel does not respond.
In such cases, the AC / DC voltage converter is often faulty, which is combined with the main board MSDV3222-ZC01-01. It is necessary to measure its secondary output voltages, and in case of their absence, check the serviceability of the power switches of the converters and rectifier diodes for the presence of a possible short circuit.
In case of breakdowns in the secondary circuits, the converter can emergencyly operate in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse usually breaks.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. It can be supply, damper circuits, or elements of OOS (negative feedback) stabilization. The reason for the breakdown of the power switch may also be PWM SW23-6 PWM. It is checked only by replacement with a known good one.
- There is no image, there is sound, it responds to the remote control. Or the image may appear for a second when turned on and immediately disappears.
The most likely in these cases is a malfunction of the LED backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It is impossible to check the line of series-connected LEDs without a special current source, and for this purpose it is not safe to use any voltage sources above 12V for them. Then it remains only to open the panel and check each LED separately. Usually, Chinese 9V-powered multimeters light up a single 3-volt LED, if you connect the probes in the forward direction, the red probe to the anode, and the 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 turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the motherboard MSDV3222-ZC01-01 should begin by checking the stabilizers and power converters needed to power the chips 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: MSD308BT-SW, SPI Flash: GD25Q64B, EEPROM T-con 24C16, Scaller: NT71263FG-300 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.
Attention! Users and owners of MTV-2424LT2 TVs who do not have the appropriate qualifications, knowledge and experience are strongly advised against self-repair attempts in order to avoid negative consequences that could lead to complete non-repairability of the device.

SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    MYSTERY MTV-3224LT2 Chassis MSDV3222-ZC01-01 (MSDV3222-YL01-01)


 To reduce the backlight current in LED drivers with the AP3039AM controller and the AP3608EM terminal stage (AP3039AM-G1 & AP3608EM-G1), the AP3608EM (AP3608E) microcircuit should proportionally increase the resistor from terminal 14 (ISET) to the housing. The maximum current in each channel (in milliamperes) for the Rset resistor (in kilo-ohms) is determined from the ratio 1.194V / Rset. In channels connected in parallel, the currents add up.
Repair MainBoard
The appearance of the MainBoard MSDV3222-ZC01-01 is shown in the figure below:
The motherboard MSDV3222-ZC01-01 is made on a single chassis with a power module and an inverter to power the LED panel. The MSD308BT-SW multi-function control processor with built-in scaler is used. Repair of the power module is carried out according to standard technology - verification of power cells, electrolytic capacitors and secondary supply voltages. The following is a functional check of stabilizers and converters for powering the internal nodes of the processor and LCD panel. It should be borne in mind that if there are problems with the software in the SPI Flash chips manufactured by WINBOND, it is advisable to replace the chip itself with the contents of the software.
MSDV3222-ZC01-01 can be used in TVs:
BBK LEM3284DT2 (Panel LSC320AN02), MYSTERY MTV-2229LT2 (Panel M215HTN01.1 ), MYSTERY MTV-2429LT2 (Panel M240HTN01.2), MYSTERY MTV-2223LT2 (Panel LC215DTBA), MYSTERY MTV-2431LT2 (Panel V236BJ1 600), MYSTERY MTV-1924LT2 (Panel HT185WXF-100), MYSTERY MTV-3228LT2 (Panel LK315T3HB94), MYSTERY MTV-3023LT2 (Panel MT3151A05), MYSTERY MTV-2228LT2 (Panel RUNTK0001ZDP2), MYSTERY MTV-1929LT2 (Panel V185BJ1-PE1), MYSTERY MTV-3223LT2 (Panel LC315TU3A), MYSTERY MTV-3224LT2 (Panel HV320WX2-20A), MYSTERY MTV-3028LT2 (Panel ST2751A01-3), MYSTERY MTV-2428LT2 (Panel V236BJ1-P01), MYSTERY MTV-2424LT2 (Panel HM236WU8-200 ), MYSTERY MTV-4030LT2 (Panel V400HJ6-PE1), MYSTERY MTV-3031LT2 (Panel V290BJ1-PE1), MYSTERY MTV-3226LT2 (Panel V320BJ7-PE1).
Main features of the MYSTERY MTV-2424LT2 device:
Installed matrix (LED-panel) HM236WU8-200.
The matrix control uses the Timing Controller (T-CON) HM236WU1-100.
To power the backlight LEDs, a converter is used, combined with the main board MSDV3222-ZC01-01, controlled by a PWM controller AP3039AM-G1, AP3608EM.
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.
MainBoard - the main board (motherboard) is an MSDV3222-ZC01-01 module, using CPU chips: MSD308BT-SW, SPI Flash: GD25Q64B, EEPROM T-con 24C16, Scaller: NT71263FG-300 and others.

 MYSTERY MTV-2424LT2 TV with HM236WU8-200 LCD, 24 "(61 cm) diagonal size in 16: 9 format. The LED-panel of this TV has LED end lighting - 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 graphic decomposition according to the standard 1080p (Full HD). The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in standards 480i, 480p, 5 76i, 576p, 720p, 1080i Supported media file formats: MP3, JPEG.
The power of the sound system 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), AV, audio x2, component, VGA, HDMI x2, USB. 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: 800x600, 1024x768, 1360x768, 1920x1080.
A digital tuner is capable of receiving television channels in the DVB-T, DVB-C, DVB-T2 standards.
Dimensions: With stand 642x444x209 mm, Without stand 570x345x70 mm.
Attention! The HM236WU8-200 panel of the MYSTERY MTV-2424LT2 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.