Wednesday, 29 April 2020

REPAIR / SERVICING TV MYSTERY MTV-2428LT2

Technical description and composition of the MYSTERY MTV-2428LT2 TV, type of panel and applicable modules. The composition of the modules.
MYSTERY LED
Model: MTV-2428LT2
Chassis / Version: MSDV3222-ZC01-01
Panel: V236BJ1-P01
LED backlight: LED236D44-ZC14-01 (A) 30323644201
T-CON: V236BJ1-XC01; CM1801, CM501, CM601, 428RP (ST24C128)
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
IC MainBoard: CPU: MSD308BT-SW; SPI Flash: MX25L6406E M2I; Scaler: NT71263FG-300; EEPROM: 24C16;
Tuner: LHD
Technical Specifications MTV-2428LT2
MYSTERY MTV-2428LT2
General repair guidelines for TV LCD LED
Diagnostics of malfunctions and repairs of MYSTERY MTV-2428LT2, as well as other electronic devices, it is recommended to start with an external examination of the external and internal elements. A visible physical change in some components can sometimes suggest a further troubleshooting direction. 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-2428LT2 TV does not turn on, does not respond to the remote control and buttons, any indicators on the front panel do not light up or blink, and there are no sounds and no signs of operability at all, the power module is most likely faulty or there is no power standby mode. First of all, it is necessary to replace the swollen capacitors of the rectifier filters, if any. If the mains fuse is cut off in the power supply, in most cases a breakdown of the power key (s) is detected, which can be integrated with the PWM controller, or a separate field-effect transistor can be used. The rectifier bridge diodes and the electrolytic capacitor of the mains rectifier filter should also be checked.
As a rule, the keys in switching power supplies (SMPS) are reliable enough and rarely fail for no reason to be looked for by checking other components of the circuit - electrolytic capacitors, resistors and semiconductor elements of the primary circuit. The PWM chip is verified by replacing it with a known good one.
If the MYSTERY MTV-2428LT2 has no image, there is sound and the channels are switched, there is a possibility of a malfunction in the backlight LED circuit of the V236BJ1-P01 panel, or their power converter - LED driver. Sometimes, when turned on, the image appears and immediately disappears. In such cases, it is necessary to check the electrolytic capacitors of the power filter of the LED driver itself, including in the secondary rectifier of the main PSU.
In case of breaks in the LED circuit, a complete disassembly of the panel is required, the LEDs are checked for an open circuit, as well as the reliability of the connections in the connectors and rations of the terminals.
To check the LED lines for breaks without disassembling the panel, for example, a current source will help. It is impossible to open series-connected PN junctions with a simple multimeter, a voltage of the order of several tens of volts is required.
On the motherboard MSDV3222-ZC01-01, in the event of a malfunction, you should first check the performance of all the stabilizers and power converters of the microcircuits, and also, if necessary, update the software (software).
In some cases, to repair the MB board (SSB), it may be necessary to replace the chips - CPU: MSD308BT-SW; SPI Flash: MX25L6406E M2I; Scaler: NT71263FG-300; EEPROM: 24C16; to new or obviously serviceable. In cases where BGA technologies are used, defects are usually localized by the heating method.
Before changing the LHD tuner, 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 check the software for correctness.
It should be remembered! Attempts to repair the TV MYSTERY MTV-2428LT2, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!

FIRMWARE FOR SPI FLASH  ----------->   MYSTERY MTV-2428LT2, Main: MSDV3222-ZC01-01, Panel: V236BJ1-P01

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-2428LT2 device:
Installed matrix (LED-panel) V236BJ1-P01.
The matrix control uses the Timing Controller (T-CON) V236BJ1-XC01 ;.
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: MX25L6406E M2I; Scaler: NT71263FG-300; EEPROM: 24C16; and others.
The LHD tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: CHIMEI INNOLUX
Model: V236BJ1-P01
Type: a-Si TFT-LCD, CELL
Diagonal size: 23.6 inch
Resolution: 1366x768, WXGA
Display Mode: MVA, Normally Black, Transmissive
Active Area: 521.471x293.184 mm
Surface: Antiglare (Haze 1%), Hard coating (3H)
Glass Depth: 0.50 + 0.50 mm
Transmissivity: 5.5% (with Polarizer)
Contrast Ratio: 3000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 8.5 (G to G)
Frequency: 60Hz
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V

 MYSTERY MTV-2428LT2 TV with V236BJ1-P01 LCD, 24 "(61 cm) diagonal size of 16: 9 format. The required brightness of the screen is 230 cd / m² 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, 1080p. Supported media file formats: MP3, JPEG.
The power of the sound system 10 W (2x5 W) provides 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, 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: 640x480, 800x600, 1024x768, 1280x1024, 1360x768.
A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Dimensions: With stand 642x444x209 mm, Without stand 570x345x70 mm.
Attention! The V236BJ1-P01 panel of the MYSTERY MTV-2428LT2 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.