REPAIRING AND NOT THROWING AWAY

REPAIRING AND NOT THROWING AWAY

Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and technical information about Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

If you go into the profession, you will obtain or have access to a variety of tech tips databases HERE IT IS Master Electronics Repair !.

These are an excellent investment where the saying: 'time-is-money' rules. However, to learn, you need to develop a general troubleshooting approach - a logical, methodical, method of narrowing down the problem. A tech tip database might suggest: 'Replace C536' for a particular symptom. This is good advice for a specific problem on one model. However, what you really want to understand is why C536 was the cause and how to pinpoint the culprit in general even if you don't have a service manual or schematic and your tech tip database doesn't have an entry for your sick TV or VCR.

While schematics are nice, you won't always have them or be able to justify the purchase for a one-of repair. Therefore, in many cases, some reverse engineering will be necessary. The time will be well spent since even if you don't see another instance of the same model in your entire lifetime, you will have learned something in the process that can be applied to other equipment problems.
As always, when you get stuck, checking out a tech-tips database may quickly identify your problem and solution.In that case, you can greatly simplify your troubleshooting or at least confirm a diagnosis before ordering parts.

Happy repairing!
Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

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..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

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Tuesday, 3 March 2020

REPAIR / SERVICING TV LG 47LM640T

Technical description and composition of the LG 47LM640T TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 47LM640T
Chassis / Version: LD22E
Panel: LC470EUG (PE) (F2)
LED backlight: 6920L-0001C (6916L0890B)
LED driver (backlight): integrated into PSU; 67.2V, 0.78A
PWM LED driver: UC2843BD1 (Step-Up LED), AAT2430AISX, R5F100BCAFP
MOSFET LED driver: STF19NF20, PHT4NQ10LT
Power Supply (PSU): EAX64744204 (1.3), EAY62608903, LGP4247L-12LPB-3PM
PWM Power: L6599AD (PWM Resonant), FAN7930BG (PFC), STR-A6059H (Standby)
MOSFET Power: STF13NM60N (PFC), STF10NM60N
MainBoard: EAX64307910 (1.0) EBR75226854, SAA35926654, SAA35948950
IC MainBoard: CPU: LGE2112; DRAM: H5TQ2G63BFR-PBC
Tuner: TDSN-G351D
Control: AKB73615303; Wi-Fi Module TWFM-B003D, EAT61613401, BEJTWFMB003D
Specifications 47LM640T
LG 47LM640T
General repair guidelines for TV LCD LED
A malfunction of the power supply is often manifested corny - the TV does not turn on, does not make any sounds, does not light up and does not blink with any indicators. When diagnosing and repairing the power supply, first of all, replace the swollen filter capacitors of the secondary rectifiers and check the fuse and, if it is broken, it is necessary to identify the cause. Often in such cases, an avalanche (thermal) breakdown is detected in the power semiconductor elements of the module — rectifier diodes and transistors in the primary circuit.
A breakdown of the power switch of the pulse converter is often triggered by other elements, for example, in the stabilization or control circuits of this switch, as well as by the damper elements in its drain and TPI winding.
Sometimes the LG 47LM640T TV does not have an image, but there is sound, or the image appears and immediately disappears. In this case, there is a possibility of a malfunction of the LED driver - power converter for the backlight LEDs of the LC470EUG (PE) panel (F2), or a break in the LED circuit is possible. In such cases, first of all, it is necessary to verify the operability of the electrolytic capacitors of the filter by supplying the backlight unit.
In case of breaks in the LED circuit, a complete disassembly of the panel is required, the LEDs are checked for an open circuit, as well as the reliability of the connections in the connectors and rations of the terminals.
When trying to detect a break in the LED lines, it should be taken into account that it is difficult to do this without disassembling the panel. For example, a current source is needed to open PN junctions connected in series.
In cases of attempts to repair the motherboard EAX64307910 (1.0) EBR75226854, SAA35926654, SAA35948950, it is necessary to check the operability of the linear stabilizers and power converters of its microcircuits and, if possible, update the software (software). BGA chips can sometimes be diagnosed with local heating.
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: LGE2112; DRAM: H5TQ2G63BFR-PBC and other possible defective components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
The malfunction of the TDSN-G351D tuner is established after checking the software and all the supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
Owners and users of the LG 47LM640T TV must remember that self-repair without special knowledge, skills and qualifications can be fraught with negative consequences that can lead to complete non-repairability of the device!
Service manual / schematic diagram ----------------> LG CHASSIS: LD22E MODEL 47LM640S, 47LM640T, 47LM640S/640T-ZA.

psu  schematic diagram ----------------> EAX64744204 (EAY62608903) LGP4247L-12LPB-3PM.

Panel backlight - Led cool: 6922L-0021A
Led left: 1242 47 ART TV REV0.0 L-Type 6920L-0001C, 6916L0890B
Led right: 1242 47 ART TV REV0.0 R-Type 6920L-0001C, 6916L0890B

 To reduce the backlight current in LED drivers with the AAT2430AISX controller, increase the resistance of the resistor from terminal 50 (ISET) to the housing, for example, from 3 KOhm to 4.7 KOhm. Currents will proportionally decrease in each of the 16 channels. With a parallel connection of channels, currents are summed.



 The appearance of the MainBoard EAX64307910 is shown in the figure below:
EAX64307910
PSU Advanced
The EAX64744204 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 FAN7930BG 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 device LG 47LM640T:
Installed matrix (LED-panel) LC470EUG (PE) (F2).
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by a PWM controller UC2843BD1 (Step-Up LED), AAT2430AISX, R5F100BCAFP. As the power elements of the LED driver, keys of the STF19NF20, PHT4NQ10LT type are used.
The necessary supply voltages for all nodes of the LG 47LM640T TV are generated by the EAX64744204 power module or its analogs using L6599AD (PWM Resonant), FAN7930BG (PFC), STR-A6059H (Standby) microcircuits and power switches of the STF13NM60N (PFC), STF10NM60N type.
MainBoard - the main board (motherboard) is an EAX64307910 module, using CPU chips: LGE2112; DRAM: H5TQ2G63BFR-PBC and others.
The TDSN-G351D tuner provides television reception and channel tuning.
Posted By: FRANK at 01:55
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