Friday 1 May 2020

REPAIR / SERVICING TV MYSTERY MTV-4217LW

Technical description and composition of the MYSTERY MTV-4217LW TV, type of panel and applicable modules. The composition of the modules.
MYSTERY LED
Model: MTV-4217LW
Chassis / Version: MSDV3209-ZC01-01
Panel: T420HW09 V.9 (FHD) // T420HW08 V8
LED driver (backlight): integrated into PSU; LED: 98V
PWM LED driver: OB2263, AP3616M28-G1
MOSFET LED driver: MDF0765 (7A 600V)
Power Supply (PSU): TV4205-ZC02-01
PWM Power: FAN7930 (PFC), OB2263, OB2273
MOSFET Power: FDPF18N50
MainBoard: MSDV3209-ZC01-01 (D)
IC MainBoard: CPU: MSD309PX-LF-SW, SPI FLASH: MX25L6405D
Tuner: DT58WT-3RB-E
Control: IR: TV3262-ZC25-01 (A)
Technical Specifications MTV-4217LW
MYSTERY MTV-4217LW
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-4217LW TV, as well as the external elements of the case. Often, by the external signs and nature of the damage to the elements, it becomes possible to draw some conclusions and determine a further algorithm for finding a defect before making the necessary measurements at control points. In some cases, faulty elements can be seen with the naked eye, for example, charred resistors or swollen metal-ceramic capacitors, or electrolytic in rectifier filters. Ring cracks formed in the soldered terminals of transformers or heating elements of the circuit are also frequent sources of many malfunctions with a variety of external manifestations.
In cases when the MYSTERY MTV-4217LW 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 when turning on, the TV4205-ZC02 power supply module is most likely to be faulty -01 or there is no processor power on the motherboard (a typical defect of some MYSTERY TVs). 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.
It should be remembered that in the practice of repair, usually the power switches in switching power supplies (SMPS) do not fail due to their poor quality and, in such cases, it is necessary to look for the cause that led to a malfunction and provoked a breakdown of the key. Most often, the culprits of the accident are dried electrolytic capacitors or dangling resistors in the primary circuit, or the PWM controller chip itself may be faulty. It is also necessary to check all the semiconductor elements of the stabilization circuit in the primary and secondary circuits.
Sometimes the MYSTERY MTV-4217LW TV does not have an image, but there is sound, or the image appears and immediately disappears. In this case, there is a high probability of a malfunction of the T420HW09.V9 FHD panel backlight LED converter, or a break in the LED circuit is possible. In such cases, first of all, it is necessary to verify the serviceability of all the electrolytic capacitors of the filter by supplying the LED driver itself, including in the power supply unit (power supply unit).
To check the health of the LEDs and contact connections in their power circuit, the panel must be disassembled.
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.
Repair of the motherboard MSDV3209-ZC01-01 (D) must begin with the diagnosis and verification of all linear stabilizers or power converters of its microcircuits. Sometimes it may be necessary to update the software (software) - flashing FLASH or EEPROM.
In cases of complex repairs of MB (SSB) and in the presence of the necessary skills and equipment, sometimes it may be necessary to replace its CPU chips: MSD309PX-LF-SW, SPI FLASH: MX25L6405D and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
If there is no reception of television channels, but the TV is working properly from external devices, first of all, check the voltage of the tuner DT58WT-3RB-E.
Once again, remind users! Attempts to self-repair a TV MYSTERY MTV-4217LW without the appropriate qualifications and experience can lead to its complete non-repairability!


SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    Main MSDV3209-ZC01-01 Schematic diagram

FIRMWARE FOR SPI FLASH  ----------->   MYSTERY MTV-4217LW, Main: MSDV3209-ZC01-01(D), Panel: T420HW09.V9 FHD

SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    TV4205-ZC02-01 Schematic diagram

 T420HW08 V.8 Backlight: LED42D15-ZC14-01 (D) 3034201520D, LED42D15-ZC14-02 (D) 3034201520E, LED42D15-ZC14-03 (D) 3034201520F, LED42D15-ZC14-04 (D) 3034201520G.

To reduce the backlight current in LED drivers with the AP3616M28-G1 terminal stage, the total resistance of the resistors from terminal 22 (ISET AP3616M28) to the housing should be proportionally increased. The maximum current in each of the 16 channels is 75 mA. To increase the current in the diodes, the channels are connected in parallel. The current in milliamperes in each channel is determined from the calculation of 1560 * 1.194 / Rset, where Rset is the resistance from the ISET output to the housing in kilo-ohms.
Repair MainBoard
The appearance of the MainBoard MSDV3209-ZC01-01 is shown in the figure below:
MainBoard MSDV3209-ZC01-01 uses a multifunctional microprocessor of the type MSD309PX or MSD308PX with an integrated scaler. Two RAM chips W9751G6IB are used as RAM. SPI Flash MX25L6406EMI-12G is made in the SOP-16 (16 pin) package.
It is advisable to start the repair of the motherboard by checking the voltage + 5V standby mode. In the operating mode, it is necessary to check the operability of linear stabilizers and power converters of the processor, memory, panel and other components of the board.
MSDV3209-ZC01-01 can be used in TVs:
BBK LEM3281FDT (Panel V315B1-LE9 REV.C1), BBK LEM3285FDTG (Panel V315H4-LE7 REV.C1), BBK LEM1949DT (Panel HT185WX3-100), BBK LEM3248DT (Panel V315B1-LE7 REV.C1), BBK LEM2665FDTG (Panel V260H1-LE8), BBK LEM3249FDT (Panel V315H4-LE8), BBK LEM2449FDT (Panel M236MWF7), BBK LEM3282DT (Panel V315B1-LEA), MYSTERY MTV-4018LW (Panel T390HVN01.0), MYSTERY MTV-4022LW (Panel M390HJ1-P01), MYSTERY MTV-4214LW (Panel T420HW08 V.5 FHD), MYSTERY MTV-3214LW (Panel V315H4-LE2 Rev.C1), MYSTERY MTV-4217LW (Panel T420HW09 V.9 (FHD)), MYSTERY MTV-3220LW (Panel V315H4-LE7).
PSU Advanced
The TV4205-ZC02-01 power supply module is made using the Power Factor Correction (PFC) scheme to eliminate multiple AC harmonics introduced into the power supply by the device. The PFC node is a Step-Up Converter based on the FAN7930 PWM controller, which evenly distributes high-frequency pulses of the charging current of the electrolytic capacitor of the rectifier filter of the mains voltage over a period of 50 Hz. The current of its charge in this case will already be determined not by its reactance (usually 10-30 ohms for the network frequency), but by the elements of the converter. As a result, a change in the amplitude of the pulses (envelope) of the consumed current of the converter will repeat the shape and phase of the input sinusoidal voltage. The availability of an increased voltage (about + 380V) in the operating mode on the capacitor of the line filter indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the MYSTERY MTV-4217LW device:
Installed matrix (LED-panel) T420HW09 V.9 (FHD) or T420HW08 V8.
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by the OB2263 PWM controller, AP3616M28-G1. As power elements of the LED driver, keys of the type MDF0765 (7A 600V) are used.
The necessary supply voltages for all nodes of the MYSTERY MTV-4217LW TV are generated by the TV4205-ZC02-01 power supply module or its analogs using FAN7930 (PFC), OB2263, OB2273 microcircuits and FDPF18N50 type power switches.
MainBoard - the main board (motherboard) is an MSDV3209-ZC01-01 module, using CPU chips: MSD309PX-LF-SW, SPI FLASH: MX25L6405D and others.
Tuner DT58WT-3RB-E provides the reception of television programs and tuning to channels.