Technical description and composition of the LG 37LE5500 TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 37LE5500
Chassis / Version: LD03D
Panel: LC370EUH
LED driver (backlight): integrated into PSU
Power Supply (PSU): EAY60803001 - LGP37-10SLPBLD
PWM Power: VIPER27L (Standby), L6599D (PWM Resonant), HS01G (PFC)
MOSFET Power: 04N60C3
MainBoard: EAX61762608 (1) - EBT60992701
IC MainBoard: CPU: LGE3556C, NAND: 04GW3B2DN6E, RAM: NT5TU128M8DE_BD, UPD78F0513AGA-GAM-AX
Tuner: TDFR-G155D
Specifications 37LE5500
LG 37LE5500
General repair guidelines for TV LCD LED
If the 37LE5500 TV does not turn on, does not make any sounds when it is turned on, and also no indicators on the front panel light or blink - there is a high probability of a malfunction in the power module. In some cases, there may be a malfunction only in standby power. In the absence of swollen filter capacitors of the secondary rectifiers, the diagnostics of the power supply should be started by checking the fuse and, if it is broken, it is first necessary to check all the power semiconductor elements of the primary circuit - diodes and transistors for the possibility of an avalanche or thermal breakdown.
In most cases, key breakdowns in switching power supplies (SMPS) do not occur for no reason and you should look for other faulty circuit elements that could provoke a defect. This can be dried electrolytic capacitors in the primary circuit, and faulty damper elements, as well as dangling resistors or punched semiconductor elements in the stabilization circuits. Possible defective PWM PWM chip from the manufacturer.
If the LG 37LE5500 does not have an image, there is sound and the channels switch, there is a possibility of a malfunction in the backlight LED circuit of the LC370EUH 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 backlight unit.
In most cases of lack of backlight, it becomes necessary to disassemble the panel in order to check the LEDs, connectors, loops and all contact connections. If one or several LEDs does not work in one line, therefore, they are broken and should be replaced.
It is impossible to detect a break in the LED line without disassembling the panel with a simple multimeter. The LEDs are connected in series and to open their transitions, a voltage of several tens of volts is required. Ideally, a current source is suitable for such purposes. You can open the panel and check each LED separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect the probes in the forward direction to it (red probe to the anode, black to the cathode). In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as a health indicator. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
If the motherboard EAX61762608 (1) is faulty - EBT60992701, first of all it is necessary to check all the linear stabilizers and power converters of its chips, and also, if necessary, update the software (software). Sometimes you can check the health of MB only by replacement.
Board repair and replacement of CPU chips: LGE3556C, NAND: 04GW3B2DN6E, RAM: NT5TU128M8DE_BD, UPD78F0513AGA-GAM-AX are made with the necessary equipment, and the corresponding element base. Faults associated with the application of BGA processor soldering technologies can be localized by the heating method.
If there is no reception of television channels, but the TV is working properly from external devices, first of all it is necessary to check the voltage of the TDFR-G155D tuner and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
Attention! For users and owners of 37LE5500 TVs who do not have the appropriate qualifications, knowledge and experience, we categorically do not recommend attempting self-repair in order to avoid negative consequences that could lead to complete non-repairability of the device.Typical defects of LG TVs with LGE3556C processors are provoked by its severe temperature conditions and the quality of the LGE3556C processor itself.
External manifestations may be different - the tuner or external inputs do not work, or the TV does not turn on, for example, the control lamp blinks or hangs on the screen saver.
If, when the processor warms up, performance is restored, in such cases a reball can sometimes help. Then there is the opportunity to extend the life of the TV with the help of an additional heat sink or cooler.
When replacing the processor, it should be borne in mind that they are discontinued and all LGE3556C, which sellers ALIexpress send, in most cases control units, are often already faulty.
schematic diagram -------------> LG CHASSIS LD03D; 37LE5500/550N/5800/5900, LE5510/5810/5910
The appearance of the MainBoard EAX61762608 is shown in the figure below:EAX61762608
EAX61762608 can be used in TVs:
LG 32LE5500 (Panel LC320EUH (SC)(A1)), LG 37LE5500 (Panel LC370EUH), LG 32LE7500 (Panel LC320EUH (SC)(A4)).
PSU Advanced
The 37LE5500 model uses the EAY60803001 power supply unit using the PFC (Power Factor Correction) node - an active filter of the highest harmonics of the current consumption. In fact, this is a boost converter based on the ICE1HS01G PWM controller, which eliminates the charge current of the rectifier filter's electrolytic capacitor from the network directly through the open diodes when its charging current is determined by its reactance.
As a result of the operation of the converter, the envelope of the high-frequency pulses of the input current of the converter will repeat the shape and phase of the input voltage. The health of the PFC node can be indirectly judged by the presence of an increased constant voltage (about + 380V) on the capacitor of the rectifier network in operating mode.
The appearance of the power supply
Main features of the device LG 37LE5500:
Installed matrix (LED-panel) LC370EUH.
To power the backlight LEDs, a converter is used, combined with a power supply.
The necessary supply voltages for all nodes of the LG 37LE5500 TV are generated by the EAY60803001 power module or its analogs using VIPER27L (Standby), L6599D (PWM Resonant), HS01G (PFC) microcircuits and 04N60C3 type power switches.
MainBoard - the main board (motherboard) is an EAX61762608 module, using CPU chips: LGE3556C, NAND: 04GW3B2DN6E, RAM: NT5TU128M8DE_BD, UPD78F0513AGA-GAM-AX and others.
The TDFR-G155D tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC370EUH-SCA1
Type: a-Si TFT-LCD, Panel
Diagonal size: 37 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 819.4x460.9 mm
Surface: Antiglare (Haze 10%), Hard coating (3H)
Brightness: 450 cd / m²
Contrast Ratio: 1400: 1
Display Colors: 1.06B (8-bit + Dithering), CIE1931 72%
Response Time: 8/10 (Tr / Td)
Frequency: 120Hz
Lamp Type: WLED Without Driver
Signal Interface: Mini LVDS, 120 pins