Wednesday, 29 April 2020

REPAIR / SERVICING TV MYSTERY MTV-2418LW

Technical description and composition of the MYSTERY MTV-2418LW TV, type of panel and applicable modules. The composition of the modules.
MYSTERY LED
Model: MTV-2418LW
Chassis / Version: MSTV2407-ZC01-01
Panel: HM236WUA-100
LED driver (backlight): integrated into MainBoard
PWM LED driver: AP3039AM, AP3608EM-G1
Power Supply (PSU): integrated into MainBoard
PWM Power: OB2273 (PWM SOT23-6)
MainBoard: MSTV2407-ZC01-01
IC MainBoard: Cpu: MST6E181VG-LF-Z1, Spi Flash: 25Q32B
Tuner: F35WT-2A-E
Technical Specifications MTV-2418LW
MYSTERY MTV-2418LW
General repair guidelines for TV LCD LED
MYSTERY MTV-2418LW, like other electronic devices, is recommended to start troubleshooting and repair with an external inspection of the external and internal elements. Specific external damage to some elements can sometimes indicate further actions to determine the malfunction of the TV and localize the defect before the necessary measurements are taken. Ring cracks in the soldering of the leads of the heating elements, swollen electrolytic capacitors, a charred paint layer on the resistors - all this for the repairman can be a significant clue in the assumptions about the causes and consequences of the malfunction.
In cases when the MYSTERY MTV-2418LW TV does not turn on, does not respond to the remote control and buttons, no indicators on the front panel light up or blink, and there are no sounds and no signs of operability when turning on, the power module is most likely faulty or there is no power processor on the motherboard (a typical defect of some MYSTERY TVs). When diagnosing and repairing the power supply, after replacing the swollen capacitors of the secondary rectifier filters (if any), you must first check the mains fuse. When it is broken, the power elements of transistors and rectifier bridge diodes should be checked for avalanche (thermal) breakdown.
Mos-Fet keys used in switching power supplies (SMPS) rarely fail for no reason to look for when checking other circuit elements. Often the breakdown is caused by malfunctions of electrolytic capacitors or semiconductor elements in the primary circuit, or by a break in the resistors in the stabilization circuits. The PWM controller chip can also cause a breakdown of the power switch of the converter.
If the MYSTERY MTV-2418LW does not have an image, but there is sound and the TV is controlled by the remote control, a malfunction in the backlight circuits of the HM236WUA-100 panel is likely. The LEDs or the power converter - LED driver may be faulty. Often in such cases, when you turn on the TV, an image appears and immediately disappears. First of all, it is necessary to verify the operability of the electrolytic capacitors of the rectifier filter supplying the LED driver, and check the LEDs, connecting obviously known good diagnostics.
To check the health of the LEDs, as well as contact connections in the ruler circuit, it is necessary to disassemble the panel.
A break in the line of LEDs connected in series cannot be detected with a multimeter or tester without disassembling the panel. To open all the transitions, several tens of volts are needed, and it is best to use a current source for such purposes.
The motherboard MSTV2407-ZC01-01 must be checked if there is no reaction to the remote control and function buttons, the standby indicator blinks or lights up continuously. In such cases, if the converters or power regulators of the microcircuit are working, a software update may be necessary.
Sophisticated MB board repair (SSB) is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the elements Cpu: MST6E181VS-LF-Z1, Spi Flash: 25Q32B. BGA chip malfunctions are usually easy to detect by warming up.
Before replacing the F35WT-2A-E tuner, if there is no tuning for the channels, you must first check the supply voltage at its terminals.
Once again, remind users! Attempts to self-repair a TV MYSTERY MTV-2418LW without the appropriate qualifications and experience can lead to its complete non-repairability!


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

FIRMWARE FOR SPI FLASH  ----------->   MYSTERY MTV-2418LW, Main: MSTV2407-ZC01-01, Panel: HM236WUA-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-2418LW device:
The matrix (LED panel) HM236WUA-100 is installed.
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 circuit using OB2273 microcircuits (PWM SOT23-6).
MainBoard - the main board (motherboard) is an MSTV2407-ZC01-01 module, using Cpu microcircuits: MST6E181VG-LF-Z1, Spi Flash: 25Q32B and others.
The F35WT-2A-E tuner provides television reception and channel tuning.

 TV MYSTERY MTV-2418LW with LCD HM236WUA-100, diagonal size 24 "(61 cm) 16: 9 format. The required brightness of the screen 250 cd / m² is provided by LED backlight LED. 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 analogue systems PAL, SECAM. Graphic processing and digital signal generation occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, MPEG4, 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), AV, audio x2, component, SCART, RGB, 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.
The power consumed by the TV in the operating mode from the network is 50 watts.
Dimensions: With stand 642x444x209 mm, Without stand 570x345x70 mm.
Attention! The HM236WUA-100 panel of the MYSTERY MTV-2418LW 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.