Technical description and composition of the LG 27MT75S TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 27MT75S - PZ
Chassis / Version: LD46E
Panel: LM270WF5 (SS) (C1)
LED backlight: 6916L-1669A 270WF5 REV0.2
LED driver (backlight): integrated into MainBoard
Power Supply (PSU): Adapter 19V
MainBoard: EAX65648903 (1.1) EBR78571401
IC MainBoard: LGE2122, 42568RP, H5TQ2G63FFR, H5Q4G63AFRN, THGBM5G5A1JBAIR, R5F100GEA, NTP7513
Tuner: TDSQ-G601D (B)
Control: IR :: EAX65024704 EBR78550601
Specifications 27MT75S
LG 27MT75S
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The LG 27MT75S TV does not turn on, does not respond to the remote control and the control panel buttons, does not light up or blink indicators.
Failure in such cases should begin to look in the adapter power supply circuits.
The external adapter 19V power supply is not always subject to repair, especially since the owner can purchase it independently. But, in some cases, it makes sense to open it and eliminate the simple typical defects inherent in converters in pulsed sources. Then we recommend that you measure its output voltages and, if they are absent, you should check the health of the power switches and rectifier diodes of the converters for possible short-circuit.
In case of any breakdowns in the secondary circuits, the converter can operate in emergency short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key more often breaks.
Mos-Fet power switches, used in switching power supplies, sometimes fail due to a malfunction of any other elements that can put it out of operation in key mode or create an excess of the maximum permissible parameters of the switch. These can be elements supplying the PWM controller, frequency-setting or damping circuits, or negative feedback elements in the stabilization circuit. PWM controllers, in the absence of visible damage or frank short-circuit between the terminals, are checked by replacing with new, or obviously working.
- There is no image, there is sound, all other functions of the TV work. When turned on, the image may sometimes appear for a second.
The most likely in these cases is a malfunction of the LED backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
To check the health in 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 individually with a simple Chinese multimeter (powered by 9 volts) in the P-N-junction test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black 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. A zener diode PN junction indirectly indicates a LED-a
- 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 EAX65648903 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). Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - LGE2122, 42568RP, H5TQ2G63FFR, H5Q4G63AFRN, THGBM5G5A1JBAIR, R5F100GEA, NTP7513 and replace failed chips with new ones. Some malfunctions can be associated with the use of BGA soldering technologies in modern Main Board. Typically, such defects are detected by local heating of the chip.
If the TV works normally from external devices, but does not tune into television channels, the TDSQ-G601D (B) tuner may be malfunctioning. In such cases, first of all, you should make sure that there are supply voltages at its corresponding conclusions. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the cause of the inoperability of the tuner may be a software failure.
Attention TV owners! Self-repair attempts by LG 27MT75S are not recommended by the manufacturer and can lead to serious negative consequences!
The appearance of the MainBoard EAX65648903 is shown in the figure below:EAX65648903
Main features of the device LG 27MT75S:
Installed matrix (LED panel) LM270WF5 (SS) (C1).
To power the backlight LEDs, a converter is used, combined with the main board EAX65648903.
To power all the internal components of the LG 27MT75S TV, an external adapter 19V type source is used.
MainBoard - the main board (motherboard) is an EAX65648903 module, using chips LGE2122, 42568RP, H5TQ2G63FFR, H5Q4G63AFRN, THGBM5G5A1JBAIR, R5F100GEA, NTP7513 and others.
The TDSQ-G601D (B) tuner allows you to receive television programs and tune to channels.
Additional technical information about the panel:
Brand: LG Display
Model: LM270WF5-SSC1
Type: a-Si TFT-LCD, Panel
Diagonal size: 27.0 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 597.888x336.312 mm
Surface: Antiglare, Hard coating (3H)
Brightness: 250 cd / m²
Contrast Ratio: 1000: 1
Display Colors: 16.7M (6-bit + Hi-FRC), CIE1931 72%
Response Time: 14 (G to G)
Frequency: 60Hz
Lamp Type: WLED Without Driver
Signal Interface: LVDS (2 ch, 8-bit), 30 pins
Voltage: 5.0V