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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Wednesday, 4 March 2020

REPAIR / SERVICING TV LG 55LB720V

Technical description and composition of the LG 55LB720V TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 55LB720V 55LB720V-ZG.BRUWLJU
Chassis / Version: LD42B
Panel: LC550DUH (PG) (F1)
LED backlight: 55 V14 Slim DRT Rev0.0 1 / R1-Type / R2-Type / L1-Type / L2-Type
LED driver (backlight): integrated into PSU
PWM LED driver: iW7025-00
MOSFET LED driver: 4NQ10L
Power Supply (PSU): EAX65424001 (2.4) LGP55K-14LPB 3PCR00364C
PWM Power: MAP8800 (PFC), ICE3BR4765JZ, NCP1034DG
MOSFET Power: 13N60M2
MainBoard: EAX65384003 (1.2) EBR78599402
IC MainBoard: CPU: LG1311; DRAM: H5TQ4G63AFR-PBC; EEPROM: AT24C256C, EMMC: THGBMAG6A2JBAIR
Tuner: TDJM-G101D EBL1400501
Control: WIFI: LGSBW41 EAT6209330
Technical Specifications 55LB720V
LG 55LB720V
General repair guidelines for TV LCD LED
Possible malfunctions
- LG 55LB720V does not turn on, the indicators on the front panel do not light or flash. The TV does not respond to the control buttons and the remote control.
Often in such cases, the EAX65424001 power module is faulty. It is necessary to measure its output voltages and, if they are absent, check the power switches (13N60M2) and rectifier diodes for the probability of short circuit in the converters.
In case of any breakdown of semiconductors in the secondary circuits, the converter can usually work normally in emergency short circuit mode. There are no output voltages. And with a short circuit in the power elements of the primary circuit, as a rule, the mains fuse breaks and less often the current sensor at the source of the key.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM) MAP8800 (PFC), ICE3BR4765JZ, NCP1034DG, in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- 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.
Usually in such cases, a malfunction is detected in the backlight nodes of the LED panel. 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 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.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the EAX65384003 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). Sometimes they require checking or replacing (if necessary) the elements of the MainBoard - CPU: LG1311; DRAM: H5TQ4G63AFR-PBC; EEPROM: AT24C256C, EMMC: THGBMAG6A2JBAIR. In cases where the BGA processor is used, its malfunction is usually detected by the local heating method.
If a TDJM-G101D EBL1400501 tuner is suspected of malfunction, first of all, it is necessary to verify the correctness of the software, as well as the presence of the necessary power supply voltage levels and data exchange pulses with the processor via the I2C bus at the corresponding tuner pins.

Once again, remind users! Attempts to self-repair the LG 55LB720V TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!



Service manual / schematic diagram ------------> LG 55LB720V 55LB720V-ZG Chassis LD42B.

manual / ------------> WiFi LG Wi-Fi Module LGSBW41




 The appearance of the MainBoard EAX65384003 is shown in the figure below:
EAX65384003
EAX65384003 can be used in TVs:
LG 47LB650V ZE (Panel LC470DUH (FG) (P2)), LG 42LB631V ZL (Panel LC420DUH (FG) (A1)), LG 39LB650V (Panel T390HVJ01.2), LG 55LB673V ZB (Panel LC550DUH (PG)(F1)), LG 47LB677V (Panel LC470DUH (FG)(F1)), LG 42LB673V (Panel LC420DUH (PG)(F1)), LG 47LB673V (Panel LC470DUH (PG)(F1)), LG 32LB652V 32LB652V-ZA.BRUWLDU (Panel LC320DUH (FG)(P2)), LG 50LB653V (Panel LC500DUH (FG)(P1)), LG 42LB652V 42LB652V-ZA.BRUWLJU (Panel LC420DUH (FG)(P2)), LG 55LB720V 55LB720V-ZG.BRUWLJU (Panel LC550DUH (PG)(F1)).
The appearance of the power supply
Main features of the device LG 55LB720V:
Installed matrix (LED-panel) LC550DUH (PG) (F1).
To power the backlight LEDs, a converter is used, combined with a power supply, controlled by the iW7025-00 PWM controller. As power elements of the LED driver, keys of the 4NQ10L type are used.
The necessary supply voltages for all nodes of the LG 55LB720V TV are generated by the EAX65424001 power module or its analogs using MAP8800 (PFC), ICE3BR4765JZ, NCP1034DG microcircuits and 13N60M2 type power switches.
MainBoard - the main board (motherboard) is an EAX65384003 module, using CPU chips: LG1311; DRAM: H5TQ4G63AFR-PBC; EEPROM: AT24C256C, EMMC: THGBMAG6A2JBAIR and others.
Tuner TDJM-G101D EBL1400501 provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: LG Display
Model: LC550DUH-PGF1
Type: a-Si TFT-LCD, Panel
Diagonal size: 55 inch
Resolution: 1920x1080, FHD
Display Mode: IPS, Normally Black, Transmissive
Active Area: 1209.6x680.4 mm
Surface: Antiglare (Haze 1%), Hard coating (2H)
Brightness: 450 cd / m²
Contrast Ratio: 1400: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 8/10 (Tr / Td)
Frequency: 120Hz
Lamp Type: WLED Without Driver
Signal Interface: EPI, 100 pins
Voltage: 12.0V
Posted By: FRANK at 07:55
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