Monday, 24 August 2020

REPAIRING / SERVICING TV DNS M24AM2

Technical description and composition of the DNS M24AM2 TV, panel type and modules used. The composition of the modules.
DNS LED
Model: M24AM2
Panel: M236HGE-P02
T-CON: V236H1-L01-X + C
LED driver (backlight): MKN5350-V1.3
Power Supply (PSU): Adapter 12V 5A
PWM Power: PWM
MainBoard: T.MS18VG.62B 11505
IC MainBoard: CPU: MST6M181VG, Spi Flash: 25Q32BSIG, Sound: 1517P
Tuner: CDT-3SP512-36
Appearance
DNS M24AM2
General recommendations for TV LCD LED repair
If the DNS M24AM2 does not turn on, none of the control lamps on the front panel will light up or blink, therefore, there is a very high probability of a malfunction of the Adapter 12V 5A power supply module. In some cases, only the processor power regulator may be faulty. After checking the mains fuse and power elements of the primary circuit of the power supply unit, you should also check the absence of a short circuit in the loads of the secondary rectifiers.
If a breakdown of the power switch is detected, it should be remembered that in a switching power supply (SMPS) it does not fail by itself without reasons that should be looked for by checking other elements of the primary circuit - electrolytic capacitors, PWM controller PWM, which can be checked only by replacement, as well as other semiconductor elements (diodes, transistors, zener diodes).
If the DNS M24AM2 has no image, but there is sound, there may be a malfunction of the backlight LEDs of the M236HGE-P02 panel or their power converter - LED driver.
In case of breaks in the LED circuit, it is necessary to completely disassemble the panel, check the LEDs for breakage, as well as the reliability of the connections in the connectors and the soldering of the connector pins.
To check the health of the LED circuit, it is better to use a current source with a maximum voltage of 200V. We do not recommend using any voltage sources for this purpose. You can check each LED separately with a simple Chinese multimeter (powered by 9 volts) in the P-N transition test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black one to its cathode, then the 3-volt LED will light up slightly, and in the opposite direction you can detect the transition of the emergency zener diode. The serviceability of the PN junction of the Zener diode indirectly indicates the serviceability of the LED-a
Repair of the T.MS18VG.62B 11505 motherboard must begin with diagnosing and checking all linear stabilizers and power converters of its microcircuits. Sometimes it may be necessary to update the software (software) - flashing FLASH or EEPROM.
Complicated MB (SSB) repair is possible only in the conditions of a service center with the necessary equipment. Checking or replacing CPU elements: MST6M181VG, Spi Flash: 25Q32BSIG, Sound: 1517P requires the necessary training and professional skills in repairing modules at the component level. Problems associated with BGA soldering technologies can be diagnosed by the warm-up method.
If the TV operates normally from external devices, but does not tune to TV channels, the CDT-3SP512-36 tuner may be faulty. In such cases, first of all, you should make sure that there are supply voltages at its corresponding terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the reason for the inoperability of the tuner may be a software failure.
Attention to users! Self-repair of the DNS M24AM2 TV without proper qualifications and experience can lead to its complete non-repairability!

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Additional MainBoard Repair
The appearance of the MainBoard T.MS18VG.62B is shown in the figure below:
T.MS18VG.62B
T.MS18VG.62B can be used in TVs:
BBK LEM2483F (Panel LG LC 230EUE(TD)(A1)), BBK LEM1983 (Panel LM185WH2 (TL)(A1)), DNS M24AM2 (Panel M236HGE-P02), DNS E16A90 (Panel LP156WH4 (TL)(A1)), ERISSON 23LEN60 (Panel LM230WF5), ERISSON 22LEN60 (Panel LS215AFTNO), ERISSON 24LEN60 (Panel LM230WF5 ), ERISSON 15LEN60 (Panel B156XW02 V.2), IZUMI TLE22F750B (Panel M215HGE-L10), RUBIN RB-19S2U (Panel V185B1-PE1 A01 REV 1.0), SUPRA STV-LC18250FL (Panel B173RW01 V.3).
Main features of the DNS M24AM2 device:
Installed matrix (LED-panel) M236HGE-P02.
Matrix control uses Timing Controller (T-CON) V236H1-L01-X + C.
The LED driver MKN5350-V1.3 is used to power the backlight LEDs.
To power all the internal nodes of the DNS M24AM2 TV, an external adapter 12V 5A is used using PWM microcircuits.
MainBoard - the main board (motherboard) is a T.MS18VG.62B module using CPU chips: MST6M181VG, Spi Flash: 25Q32BSIG, Sound: 1517P and others.
The CDT-3SP512-36 tuner provides reception of television programs and tuning to channels.


Additional technical information about the panel:
Brand: CHIMEI INNOLUX
Model: M236HGE-P02
Type: a-Si TFT-LCD, CELL
Diagonal size: 23.6 inch
Resolution: 1920x1080, FHD
Display Mode: TN, Normally White, Transmissive
Active Area: 521.28x293.22 mm
Surface: Antiglare (Haze 25%), Hard coating (3H)
Glass Depth: 0.50 + 0.50 mm
Transmissivity: 6.3% (with Polarizer)
Contrast Ratio: 1000: 1
Display Colors: 16.7M (8-bit)
Response Time: 1.5 / 3.5 (Tr / Td)
Frequency: 60Hz
Signal Interface: LVDS (2 ch, 8-bit), 30 pins
Voltage: 5.0V