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 49LF620V

Technical description and composition of the LG 49LF620V TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 49LF620V 49LF620V-ZB
Chassis / Version: LC55H / LD55T / LB55T / LJ55T
Panel: LC490DUE (MG) (P2)
LED backlight: LG Innotek DRT 3.0 49
T-CON: 6870C-0481A
LED driver (backlight): integrated into PSU
Power Supply (PSU): EAX66203101
MainBoard: EAX66203805 (1.2)
IC MainBoard: CPU: LGE2134; NAND Flash: TC58NVG0S3HTA00; SPI Flash: MX25L8035EM2I; EEPROM: 24C256
Tuner: TDJM-G301D
Specifications 49LF620V
LG 49LF620V
General repair guidelines for TV LCD LED
Possible malfunctions
- The LG 49LF620V TV does not turn on and does not show any signs of operability at all. There is no reaction to the remote control and control buttons from the front panel.
With such manifestations, in some cases, the EAX66203101 power module is faulty. It is necessary to measure its secondary output voltages, and if they are absent, check the power switches and rectifier diodes in the converters for a short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during short circuit in the elements of the primary circuit, the mains fuse usually breaks.
Breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback (OOS) stabilization circuits. PWM controllers (PWM), if they do not have visible damage to the chassis and open short circuit between the terminals, are usually checked by replacement.
- There is no image, but there is sound and reaction to commands from the remote control. Or the image appears immediately after turning on and disappears.
In such cases, the most likely malfunction of the LED backlight elements. The reason can be both in the power supply of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
It should be remembered that it is not possible to determine the open circuit in the LED lines without disassembling the panels with a tester or multimeter without an additional device, for example, a current source. To open all PN junctions connected in series at once, a voltage of several tens of volts may be required. Then it is necessary to open the panel and check each LED separately with a multimeter. If the capabilities of your multimeter do not allow you to open the LED in the forward direction or dual LEd are used, then the PN junction of the emergency zener diode can indirectly serve as a health indicator. In case of LED-a failure, the zener diode PN junction will either be cut off or broken into short-circuit.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the EAX66203805 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). In cases of attempts to repair the MB board (SSB), it is necessary to check the serviceability of its elements - CPU: LGE2134; NAND Flash: TC58NVG0S3HTA00; SPI Flash: MX25L8035EM2I; EEPROM: 24C256 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 TDJM-G301D 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
Once again, remind users! Attempts to self-repair the TV LG 49LF620V without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!





The appearance of the MainBoard EAX66203805 is shown in the figure below:
EAX66203805
EAX66203805 can be used in TVs:
LG 32LF564U (Panel LC320DXE (MG)(A3)), LG 42LF550V (Panel LC420DUE (MG)(A6)), LG 32LF560U ZB (Panel NC320DXN VSBP5 ), LG 42LF560V (Panel LC420DUE (MG)(A3)), LG 32LF562V (Panel NC320DUN-VBBP3 (EAJ63171201)), LG 32LF564V (Panel NC320DUN VBBP3), LG 32LF560V (Panel NC320DUN-VBBP3), LG 49LF620V 49LF620V-ZB (Panel LC490DUE (MG)(P2)), LG 42LF551C (Panel LC420DUE-MGA6).
The appearance of the power supply
Main features of the device LG 49LF620V:
Installed matrix (LED panel) LC490DUE (MG) (P2).
The matrix control uses the Timing Controller (T-CON) 6870C-0481A.
To power the backlight LEDs, a converter is used, combined with a power supply.
The formation of the necessary supply voltages for all nodes of the LG 49LF620V TV is carried out by the EAX66203101 power module, or its analogues.
MainBoard - the main board (motherboard) is an EAX66203805 module, using CPU chips: LGE2134; NAND Flash: TC58NVG0S3HTA00; SPI Flash: MX25L8035EM2I; EEPROM: 24C256 and others.
The TDJM-G301D tuner provides TV reception and channel tuning.
Posted By: FRANK at 03:12
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