Technical description and composition of the LG 47LD750 TV, panel type and applicable modules. The composition of the modules.LG
Model: 47LD750 ZA
Chassis / Version: LD03B
Panel: LC470WUH (SC) (M1)
Inverter (backlight): integrated into PSU
PWM Inverter: BD9240F
Power Supply (PSU): EAX61289501 / 12 Rev: 1.2 LGP47-10TM
PWM Power: STR-W6053N, R2A20112 (PFC)
MOSFET Power: K13A60D, 5N52U
MainBoard: EAX61531909 (2) EBR66235243 EBT60881503
IC MainBoard: LGE3556C, SAA35116504, SAA35042638, ST24C16, 25X40BVSIG
Tuner: TDFR-G135D EBL60740403
Control: AKB72914208
Specifications 47LD750
LG 47LD750
General recommendations for repairing TV LCD
TV LG 47LD750 ZA, like many other electronic devices, it is advisable to start repairing by inspecting all external and internal elements. Specific external damage to some elements can sometimes indicate further actions to determine the malfunction of the TV and localization of the defect before the necessary measurements are taken. Elements with visible damage, for example, capacitors swelled up after boiling the electrolyte, charred resistors in certain nodes of the circuit, as well as ring cracks in solders will help the master to guess the causes and possible consequences of the malfunction.
If the LG 47LD750 does not turn on, no control lights on the front panel light up or blink, therefore, there is a very high probability of a malfunction of the EAX61289501 / 12 Rev: 1.2 LGP47-10TM 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 power supply circuit, it should also check the absence of a short circuit in the loads of the secondary rectifiers.
If the power keys of the pulse converter are not equal, you should pay attention to other elements in their bundling, which may be the result or cause of their breakdown.
If the LG 47LD750 does not have an image, but there is sound, there is a possibility of a malfunction of the backlight or power converter. You should also make sure that the electrolytic capacitors of the secondary rectifiers of the common power supply are working. When disabling protection in order to enable the diagnosis of a malfunction, special care should be taken, and after completion of all repair work, it is necessary to restore the circuit and the inverter protection for further safe operation of the TV.
The motherboard EAX61531909 (2) EBR66235243 EBT60881503 should be checked if there is no reaction to the remote control and function buttons, the standby indicator blinks or stays on. In such cases, if the converters or power regulators of the microcircuit are working, a software update may be necessary. In cases of attempts to repair the MB (SSB) board, it is necessary to check the serviceability of its elements - LGE3556C, SAA35116504, SAA35042638, ST24C16, 25X40BVSIG which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its conclusions with the board (it is diagnosed by heating).
Before replacing the TDFR-G135D EBL60740403 tuner, if there is no tuning for the channels, you must first check the software and the supply voltage at its terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus.
The lack of a picture in the presence of a signal from the LG 47LD750 is often caused by a malfunction of the display backlight. Moreover, the problem can be both inside the LCD panel (matrix) LC470WUH (SC) (M1), for example, a malfunction of CCFL (EEFL) lamps, and outside in their power source - an inverter.
Without backlighting, sometimes you can see a barely noticeable image with a certain successful hit of external light on the screen.
Often, to repair the backlight, disassembly of the LC470WUH LCD panel is required - a painstaking process that requires increased attention and accuracy from the master. In such cases, there is a possibility, with the slightest negligence, to damage the glass or loops and the TV may become unrepairable.
We strongly do not recommend doing such work to owners of TVs and craftsmen who do not have experience in repairing LCD panels! Moreover, at home (at the owner's home).
If there is no image in the presence of backlight, the screen becomes slightly lighter when turned on, and if the TV is open, the light from the lamps can be seen through the holes in the panel case.
In this case, there may be a malfunction inside the panel, damage to strips, loops, the T-CON board (Timing Controller) may be defective. But the main board MainBoard EAX61531909 often turns out to be faulty, a software failure is also possible.
In such cases, the master first of all needs to check the main supply voltage of the panel at the LVDS connector, the fuses on the T-CON board or the panel brackets, as well as the supply and reference voltages for line and column drivers - VGH, VGL, Vcom.
If all of the above measurements are within the normal range, then the oscilloscope needs to track the passage of LVDS signals from the MainBoard EAX61531909, as well as synchronizing signals from T-CON to loops with drivers.
Typical defects of LG TVs with LGE3556C processors are provoked by its severe temperature conditions and the quality of the LGE3556C processor itself.It is necessary to remember to users that attempts to self-repair a LG 47LD750 TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!
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.
MAIN: EAX61531909(2) EBR66235243 0028
LGE3556C, SAA35116504/Ver.3.6.5 , SAA35042633/Ver.3.6.2
Spi Flash: 25X40BVSIG, Eeprom: 24C16, 24H01RP
USB2512A_AEZG, MP2208DL, UPD78F0513AGA-GAM-AX, MP2212DN, SC4215ISTRT
DOWNLOAD SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> LG 47LD750-ZA, 47LD750N-ZA, 47LD751-ZB, 47LD780-ZA, 47LD790-ZA, CHASSIS LD03B
The appearance of the MainBoard EAX61531909 is shown in the figure below:EAX61531909
EAX61531909 can be used in TVs:
LG 32LD750 ZA (Panel LC320WUH (SC) (M1)), LG 32LD650 (Panel LC320WUG (SC) (A1)), LG 47LD750 ZA (Panel LC470WUH (SC) (M1)).
PSU Advanced
On the 47LD750 TV, the EAX61289501 / 12 Rev: 1.2 LGP47-10TM power module is installed using the PFC (Power Factor Correction) scheme, which acts as an active filter to eliminate the higher harmonic components of the current consumption. The boost converter based on the R2A20112 PWM controller does not allow the electrolytic capacitor of the input rectifier filter to be connected to the network directly through open diodes, when the reactance (about 15-30 ohms at a frequency of 50 Hz) determines the charge current. As a result of the conversion, the charging current of the capacitor will be determined in such a way that the envelope of the high-frequency pulses of the input current will repeat the phase and shape of the sine wave of the input voltage. The health check of the PFC unit is carried out by measuring the DC voltage on the capacitor of the rectifier network. In operating mode, it should be around 380V, in standby approximately 300V.
The appearance of the power supply
Main features of the device LG 47LD750:
Installed matrix (LCD panel) LC470WUH (SC) (M1).
To power the backlight, a converter is used, combined with a power supply, controlled by a BD9240F PWM controller.
The necessary supply voltages for all nodes of the LG 47LD750 TV are generated by the EAX61289501 power module or its analogs using STR-W6053N, R2A20112 (PFC) microcircuits and K13A60D, 5N52U type power switches.
MainBoard - the main board (motherboard) is an EAX61531909 module, using chips LGE3556C, SAA35116504, SAA35042638, ST24C16, 25X40BVSIG and others.
Tuner TDFR-G135D EBL60740403 provides the reception of television programs and tuning to channels.
LG 47LD750 TV with LCD LC470WUH (SC) (M1), 47 "(119 cm) diagonal, 16: 9 format. Dynamic contrast ratio of 80000: 1 is achieved by controlling the operation of the backlight depending on the brightness of the scene.
The LC470WUH sensor and MainBoard EAX61531909 software provide viewing of broadcasts and movies in high quality HD at a resolution of 1920x1080 pixels in graphics resolution at 1080p (Full HD).
The 47LD750 TV is equipped with SMART software, built-in applications and the ability to work on the Internet. The connection to the network can be carried out via Wi-Fi wireless connection. The input analog video signal is decoded in PAL, SECAM, NTSC systems. The graphic processing of the digital signal is carried out in the 480i, 480p, 576i, 576p, 720p, 1080i, 1080p standards. Supported media file formats: MP3, WMA, MPEG4, MKV, JPEG.
Speaker sound system power 20 W (2x10 W) is provided by two speakers. The NICAM stereo audio processing system and the Sound Surround function are used.
Communication with other devices via an external interface is supported by standard input and output connectors: antenna input (RF), AV, audio x3, component, SCART, RGB, VGA, HDMI x3, USB x2, RS-232, Ethernet (RJ-45), Wi-Fi. A headphone jack is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is provided. This interface supports standard resolutions: 640x480, 800x600, 1024x768, 1280x1024, 1360x768, 1920x1080.
The digital tuner can receive TV channels in DVB-T MPEG4, DVB-C standards.
The power consumed when operating from the network is 250 W. Power supply unit EAX61289501 / 12.
Dimensions: With stand 1144x764x260 mm, Without stand 1144x704x77 mm.
Attention! The LC470WUH panel of the LG 47LD750 LCD TV is the most expensive component.
Avoid hitting the glass and putting pressure on the screen surface to avoid irreversible damage to the LCD panel!