Wednesday, 29 April 2020

REPAIR / SERVICING TV MYSTERY MTV-2424LW

Technical description and composition of the MYSTERY MTV-2424LW TV, type of panel and applicable modules. The composition of the modules.
MYSTERY LED
Model: MTV-2424LW
Chassis / Version: MSTV2407-ZC01-01
Panel: HM236WU8-100
LED driver (backlight): integrated into MainBoard
PWM LED driver: AP3039AM, AP3608EM-G1
Power Supply (PSU): integrated into MainBoard
PWM Power: SG6848 (PWM SOT23-6)
MainBoard: MSTV2407-ZC01-01
IC MainBoard: CPU: MST6E182VG-LF, SPI FLASH: 25Q32
Tuner: F35WT-2A-E
Technical Specifications MTV-2424LW
MYSTERY MTV-2424LW
General repair guidelines for TV LCD LED
Repair of electronic equipment usually begins with its external inspection and diagnosis of the malfunction. In this case, you should examine all the internal components of the MYSTERY MTV-2424LW TV, as well as the external elements of the housing. In some cases, visible external damage to the elements can suggest the direction of troubleshooting and localization of the defect even before the start of the necessary measurements at the control points of the nodes of electronic circuits. Electrolytic capacitors of filters with a swollen casing, as well as ring cracks formed in the soldered leads of heating elements, or a layer of coal on burnt resistors sometimes tell the repairman the causes of the malfunction and possible consequences.
Malfunctions of the power module can be expressed in different ways, for example, the MYSTERY MTV-2424LW does not turn on at all and the control lamps on its front panel do not light up and do not blink, and there are no signs of operability. It should be noted that with the same external manifestations, the processor power regulator (converter) may be faulty. Diagnostics and repair of the common power supply should always begin with a check of the mains fuse and the condition of the electrolytic capacitors of the secondary rectifier filters. Defective and swollen capacitors should be replaced with new ones. If the fuse breaks, it is advisable to check for a breakdown, first of all, all the power semiconductor elements of the converter and the diode bridge of the rectifier network, as well as the large electrolytic capacitor of the filter of the rectifier network.
Power switches in pulsed power supplies (SMPS) fail extremely rarely for no reason and, if they are broken, it is necessary to look for a malfunction in the stabilization circuits by checking electrolytic capacitors, semiconductor devices, and resistors in the primary circuit. The cause may be a malfunction of the PWM controller chip, which can only be checked by replacing it with a new or obviously working one.
If the MYSTERY MTV-2424LW does not have an image but there is sound, the backlight LEDs on the HM236WU8-100 panel or their power converter may malfunction. You should also make sure that the electrolytic capacitors of the secondary rectifiers of the common power supply are working.
To check the health of the LEDs, as well as contact connections in the ruler circuit, it is necessary to disassemble the panel.
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.
On the motherboard MSTV2407-ZC01-01, in the event of a malfunction, you should first check the performance of all the stabilizers or power converters of the microcircuits and, if necessary, update the software (software).
Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - CPU: MST6E182VG-LF, SPI FLASH: 25Q32 and replace failed chips with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.
The malfunction of the tuner F35WT-2A-E is established after checking the software and all the supply voltages at its terminals.
Once again, we remind TV users: you should not make attempts to repair it yourself without the appropriate knowledge, experience and the necessary qualifications! Trust the repair only to professionals with sufficient experience in the field of electronic equipment repair.

SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    MSTV2407-ZC01-01 Schematic diagram

FIRMWARE FOR SPI FLASH  ----------->   MYSTERY MTV-2424LW, Main: MSTV2407-ZC01-01, Panel: HM236WU8-100

 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 MSTV2407-ZC01-01 is shown in the figure below:
MSTV2407-ZC01-01
MSTV2407-ZC01-01 motherboard is combined with a power module. The processor is MST6E182VG, or MST6E181VG, made using BGA technology. Repair of the power module is carried out according to conventional technology, starting with checking its power elements. The following is a functional check of the converters for the processor power: + 1.3V, + 1.8V, 3.3V, based on SY8008B PWM controllers. The power supply of the built-in DDR 2.5V is generated from a 3.3V source using the P-N junction of the 1N4001 diode (3.3V-0.8V = 2.5V). Standby mode is organized from the linear stabilizer series 1117-3V3. The LCD panel is powered by either 5V or 12V, depending on the type of panel used.
MSTV2407-ZC01-01 can be used in TVs:
BBK LEM2249HD Ver2 (Panel LM215DT5D), BBK LEM2284F (Panel M215HG-LE4 Rev.C3), BBK LEM2681F (Panel V260H1-LE10 Rev. C1 ), BBK LEM2682 LEM2682DT (Panel V260B2-LE11 Rev.C1), BBK LEM3284F (Panel HV320WXC-200), Haier LE32T1000 (Panel T320XVN09.0), MYSTERY MTV-2224LW (Panel M215HG-LE4 Rev.C3), MYSTERY MTV-3222LW (Panel T320XVN01.0), MYSTERY MTV-1924LW (Panel V185B1-L17), MYSTERY MTV-3018LW (Panel V290BJ1-PE1), MYSTERY MTV-1911LW (Panel HT185WX7-100), MYSTERY MTV-1922LW (Panel V185B1-L17), MYSTERY MTV-1913LW (Panel HT185WX7-100), MYSTERY MTV-3218LW (Panel HV320WX2-20A), MYSTERY MTV-1918LW (Panel V185B1-L17), MYSTERY MTV-2213LW (Panel M215HGE-L10), MYSTERY MTV-2222LW (Panel M215HG-LE4 REV.C3), MYSTERY MTV-2418LW (Panel HM236WUA-100), MYSTERY MTV-2424LW (Panel HM236WU8-100), MYSTERY MTV-1914LW (Panel V185B1-L15 Rev.c1), MYSTERY MTV-3223LW (Panel LK315T3HB94), MYSTERY MTV-2422LW (Panel HM236WU8–100), MYSTERY MTV-3224LW (Panel T320XVN09.0), MYSTERY MTV-2218LW (Panel CLAA215FA10), MYSTERY MTV-1911WL (Panel V185B1-L15 REV.C1), MYSTERY MTV-3221LW (Panel HV320WX2-268), MYSTERY MTV-2211W (Panel M215HG-LE4 ).
Main features of the MYSTERY MTV-2424LW device:
Installed matrix (LED-panel) HM236WU8-100.
To power the backlight LEDs, a converter is used, combined with the main board MSTV2407-ZC01-01, controlled by the AP3039AM, AP3608EM-G1 PWM controller.
The power module is combined with the MainBoard and is made according to the flyback AC / DC voltage converter using SG6848 microcircuits (PWM SOT23-6).
MainBoard - the main board (motherboard) is an MSTV2407-ZC01-01 module, using CPU chips: MST6E182VG-LF, SPI FLASH: 25Q32 and others.
The F35WT-2A-E tuner provides television reception and channel tuning.


 MYSTERY MTV-2424LW TV with HM236WU8-100 LCD, 24 "(61 cm) diagonal size of 16: 9 format. The required screen brightness of 250 cd / m² is provided by LED backlighting. Contrast, as the ratio of maximum brightness to minimum, is 1000: 1. The LED-panel of this TV has end-face LED backlighting - Edge LED.The TV design and technical features 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). frequency or video signal can be processed in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i. Supported media file formats: MP3, JPEG.
The power of the sound system 6 W (2x3 W) provide 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, audio x2, component, VGA, HDMI x2, USB. 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.
The power consumed by the TV in the operating mode from the network is 40 watts.
Dimensions: With stand 642x444x209 mm, Without stand 570x345x70 mm.
Attention! The HM236WU8-100 panel of the MYSTERY MTV-2424LW 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.