Friday, 1 May 2020

REPAIR / SERVICING TV MYSTERY MTV-2225WD

Technical description and composition of the MYSTERY MTV-2225WD TV, type of panel and applicable modules. The composition of the modules.
MYSTERY
Model: MTV-2225WD
Chassis / Version: V3J08
Panel: V216B1-L04 REV.C1
Inverter (backlight): integrated into PSU
PWM Inverter: TL494C
MOSFET Inverter: ME4946
Power Supply (PSU): AYL220426
PWM Power: PWM SOT23-6
MainBoard: T.VST26.3B 10104
IC MainBoard: CPU: T80-75HCP (3F70), FLASH: 25Q80BV (5B8E), EEPROM: 24s32 (69DA)
Tuner: TDQ-ATF27WT-F
Technical Specifications MTV-2225WD
MYSTERY MTV-2225WD
General recommendations for repairing TV LCD
Possible malfunctions
- The MYSTERY MTV-2225WD TV does not turn on at all. The control lights do not light or flash. The TV on the remote control and the control panel buttons do not respond.
In such cases, the AYL220426 power supply is usually faulty. It is necessary to measure its output supply voltage, and in case of their absence, check the serviceability of the power switches of the converters and rectifier diodes for the probability of breakdown in semiconductor PN junctions.
In the event of breakdowns in the secondary circuits of the converter, it can usually fail in short circuit mode, and in the event of a short circuit in the power elements of the primary circuit, the mains fuse or current sensor at the source of the key most often breaks.
Breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback (OOS) stabilization circuits. PWM controllers (PWM) PWM SOT23-6, if they do not have visible damage to the case and open short circuit between the terminals, are usually checked by replacement.
- 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.
These manifestations can be triggered by a power module, or by defects in the inverter, as well as a distortion of the currents in the lamps due to their uneven wear. After checking all the electrolytic capacitors of the filters that are involved in the power supply of the inverter, it is necessary to ring in its converter the power switches for breakdown and the secondary windings of the transformers for an open.
Sometimes, for diagnostic purposes, inverter protection must be disabled. In such cases, special care must be taken during work, and the protection circuits should be restored immediately after the repair is completed.
- The indicator on the front panel blinks, the TV does not turn on in the operating mode, it does not respond to the remote control.
Repair or diagnostics of the T.VST26.3B 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). In cases of attempts to repair the MB (SSB) board, it is necessary to check the health of its elements - CPU: T80-75HCP (3F70), FLASH: 25Q80BV (5B8E), EEPROM: 24s32 (69DA) which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its conclusions with the board (it is diagnosed by heating).
Before changing the tuner TDQ-ATF27WT-F, if it is not possible to tune to television channels, make sure that there are supply voltages, which must be measured at the corresponding terminals of the tuner and checked for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
TV users and owners need to remember that attempts to self-repair a MYSTERY MTV-2225WD TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!


SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    Main T.VST26.3B

FIRMWARE FOR SPI FLASH  ----------->   MYSTERY MTV-2225WD V3J08, Main T.VST26.3B 10104, Panel: V216B1-L04 REV.C1



 In cases where a failure has occurred in Winbond's SPI FLASH software, we recommend replacing the chip with a new one. Often, faulty Winbond microcircuits can temporarily restore their functionality after temperature exposure, for example, when a soldering station is heated by a hairdryer. Sometimes this is enough to read the regular contents of the software.

Repair MainBoard
The appearance of the MainBoard is shown in the figure below:
T.VST26.3B
T.VST26.3B can be used on TVs:
HYUNDAI H-LCDVD2200 (Panel LTM220MT05 010), HYUNDAI H-LCD2216 (Panel M216H1-L01), IZUMI TL15H603B (Panel LTA150XH-L06), IZUMI TL15H605B (Panel LTM150XH-L06), MYSTERY MTV-2225WD (Panel V216B1-L04 REV.C1), MYSTERY MTV-2205W (Panel V216B1-L01), MYSTERY MTV-1605W (Panel HT156WX1-100).
The appearance of the power supply
Main features of the MYSTERY MTV-2225WD device:
Installed matrix (LCD panel) V216B1-L04 REV.C1.
To power the backlight, a converter is used, combined with a power supply, controlled by a TL494C PWM controller. As power elements of the inverter, keys of the type ME4946 are used.
The necessary supply voltages for all nodes of the MYSTERY MTV-2225WD TV are generated by the AYL220426 power module, or its analogs using PWM SOT23-6 microcircuits.
MainBoard - the main board (motherboard) is a T.VST26.3B module, using CPU chips: T80-75HCP (3F70), FLASH: 25Q80BV (5B8E), EEPROM: 24c32 (69DA) and others.
The TDQ-ATF27WT-F tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: CHIMEI INNOLUX
Model: V216B1-L04
Type: a-Si TFT-LCD, Panel
Diagonal size: 21.6 inch
Resolution: 1366x768, WXGA
Display Mode: TN, Normally White, Transmissive
Active Area: 477.417x268.416 mm
Surface: Antiglare (Haze 25%), Hard coating (3H)
Brightness: 400 cd / m²
Contrast Ratio: 800: 1
Display Colors: 16.7M (6-bit + Hi-FRC), CIE1931 72%
Response Time: 1.3 / 3.7 (Tr / Td)
Frequency: 60Hz
Lamp Type: 4 pcs CCFL Without Driver
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 5.0V
MYSTERY MTV-2225WD TV with V216B1-L04 LCD, 22 "(55 cm) diagonal 16:10 aspect ratio. Screen brightness of 300 cd / m² is provided by CCFL (EEFL) fluorescent lights. Contrast as the ratio of maximum brightness to the minimum is 1000: 1. It is possible to view images in high quality HD at a resolution of 1680x1050 pixels in the standard for graphic decomposition 720p (HD Ready). The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation happens in with 480i, 480p, 576i, 576p, 720p, 1080i standards Supported media file formats: MP3, MPEG4, VideoCD, SVCD, Picture CD, JPEG.
The power of the acoustic system of sound 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, S-Video, SCART, VGA, HDMI. 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.
The power consumed by the TV in the operating mode from the network is 72 watts.
Dimensions: With stand 642x444x209 mm, Without stand 570x345x70 mm.
Attention! The V216B1-L04 REV.C1 panel of the MYSTERY MTV-2225WD LCD TV is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!