Tuesday 28 April 2020

REPAIR / SERVICING TV MYSTERY MTV-1914LW

Technical description and composition of the MYSTERY MTV-1914LW TV, type of panel and applicable modules. The composition of the modules.
MYSTERY LED
Model: MTV-1914LW
Chassis / Version: MSTV2407-ZC01-01 V6L10
Panel: V185B1-L15 Rev.c1
LED driver (backlight): integrated into MainBoard
PWM LED driver: AP3039AM, AP3608EM-G1
Power Supply (PSU): integrated into MainBoard
MainBoard: MSTV2407-ZC01-01
IC MainBoard: CPU: MST6E182VG-LF-Z1, SPI FLASH: GD25Q32B
Tuner: F35WT-2A-E
Technical Specifications MTV-1914LW
MYSTERY MTV-1914LW
General repair guidelines for TV LCD LED
Diagnostics of malfunctions and repairs of MYSTERY MTV-1914LW, as well as other electronic devices, it is recommended to start with an external examination of the external and internal elements. 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. If charred resistors, swollen electrolytic or cermet capacitors, ring cracks in the solders of the terminals of transformers or heating elements are found, it is advisable to establish the causes and consequences of the malfunction that has arisen, as well as to check the connected elements and assemblies.
In the absence of any signs of operability, when the MYSTERY MTV-1914LW does not turn on and does not signal anything with the control lights on the panel, there is a possibility of a malfunction of the TV power module. With the same manifestations, the power regulator of the control processor on the motherboard may be faulty. When diagnosing and repairing the power supply, first of all, replace the swollen filter capacitors of the secondary rectifiers and check the fuse and, if it is broken, it is necessary to identify the cause. Often in such cases, an avalanche (thermal) breakdown is detected in the power semiconductor elements of the module — rectifier diodes and transistors in the primary circuit.
In most cases, key breakdowns in switching power supplies (SMPS) do not occur for no reason and you should look for other faulty circuit elements that could provoke a defect. This can be dried electrolytic capacitors in the primary circuit, and faulty damper elements, as well as dangling resistors or punched semiconductor elements in the stabilization circuits. Possible defective PWM chip from the manufacturer.
If the MYSTERY MTV-1914LW does not have an image but there is sound, the backlight LEDs of the V185B1-L15 Rev.c1 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 and contact connections in their power circuit, the panel must be disassembled.
It should be remembered that it is not possible to determine the open circuit in the LED lines without disassembling the panels with a tester or multimeter without an additional device, for example, a current source. To open all PN junctions connected in series at once, a voltage of several tens of volts may be required.
Repair or diagnostics of the MSTV2407-ZC01-01 motherboard should begin by checking the stabilizers or power converters of its microcircuits. If necessary, you should update the software (software).
When repairing an MB board, you need to check its CPU components: MST6E182VG-LF-Z1, SPI FLASH: GD25Q32B. Defective items should be replaced. If BGA chips are installed, their malfunction is usually localized by heating.
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-1914LW, Main: MSTV2407-ZC01-01, Panel: V185B1-L15 Rev.c1



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-1914LW device:
Installed matrix (LED panel) V185B1-L15 Rev.c1.
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.
MainBoard - the main board (motherboard) is an MSTV2407-ZC01-01 module, using CPU chips: MST6E182VG-LF-Z1, SPI FLASH: GD25Q32B and others.
The F35WT-2A-E tuner provides television reception and channel tuning.
MYSTERY MTV-1914LW TV with V185B1-L15 LCD display, 19 "(48 cm) diagonal size in 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. Edge LED backlighting is realized in the LED-panel of this TV - Edge LED. You can view high-quality images at a resolution of 1366x768 pixels in the standard of graphic decomposition 720p (HD Ready). The input high-frequency or video signal can be processed in analog systems . Max PAL, SECAM, NTSC Image processing and the formation of the digital signal is in 480i standards, 480p, 576i, 576p, 720p, 1080i Supported multimedia file formats:. MP3, DivX, 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, SCART, 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.
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 panel V185B1-L15 Rev.c1 LED-TV MYSTERY MTV-1914LW is an expensive and unreliable element.
Avoid any impact on the glass and pressure on the screen surface 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.