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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All posts are presented here for informative, historical and educative purposes as applicable within fair use. NOTHING HERE IS FOR SALE !

Saturday 29 February 2020

REPAIR / SERVICING TV LG 42LV571S

Technical description and composition of the LG 42LV571S TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 42LV571S ZA
Chassis / Version: LD12E
Panel: LC420EUF (SD) (A1)
LED driver (backlight): integrated into PSU
Power Supply (PSU): EAX62865401 GP4247-11SLPB
PWM Power: FAN7930B (PFC), 3BR4765JZ (Standby), L6599AD (PWM Resonant)
MainBoard: EAX64405401 (0) EBR73503602
IC MainBoard: LGE35230, K4B2G1646C-HCKO, TH58DVG4S0ETA20, NTP7400L, F0514A, M24C16
Tuner: TDFR-G256D
Specifications 42LV571S
LG 42LV571S
General repair guidelines for TV LCD LED
Possible malfunctions
- The LG 42LV571S TV does not turn on and does not show any signs of operability at all. There are no reactions to the control buttons or the remote control.
In most of these cases, a fault is detected in the EAX62865401 power module. The health of the 3BR4765JZ (Standby) converter must be checked first. Next, you should measure the output voltages of other converters (PFC and the main source), in case of their absence, check the serviceability of power switches and rectifier diodes in the converters for possible breakdown.
In case of avalanche and thermal breakdowns of diodes in the secondary circuits, the converter can operate in emergency short circuit mode, and in case of short circuit in the power elements of the primary circuit, a mains fuse or a current sensor at the source of the key usually breaks.
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. It can be supply, damper circuits, or elements of OOS (negative feedback) stabilization. Chips PWM (PWM) FAN7930B (PFC), 3BR4765JZ (Standby), L6599AD (PWM Resonant) is usually checked by replacing with new or obviously working.
- There is no image, but there is sound, it reacts to the remote control. Or the image appears when you turn it on and immediately disappears
In such cases, the most likely malfunction of the LED backlight elements. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It is impossible to check the line of series-connected LEDs without a special current source, and for this purpose it is not safe to use any voltage sources above 12V. Then it remains only to open the panel and check each LED separately. Usually, Chinese 9V-powered multimeters light up a single 3-volt LED, if you connect the probes in the forward direction, the red probe to the anode, and the black to the cathode. In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of health. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- The TV does not enter the operating mode, does not respond to the remote control. The indicator on the front panel lights constantly or blinks.
Repair or diagnostics of the EAX64405401 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). Board repair and replacement of LGE35230, K4B2G1646C-HCKO, TH58DVG4S0ETA20, NTP7400L, F0514A, M24C16 microcircuits are carried out 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 you need to check the power supply of the TDFR-G256D tuner and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
Attention to users! Self-repair of the LG 42LV571S TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!
SCHEMATIC DIAGRAM ----------->  LG CHASSIS: LD12E; MODEL: 42LV570G/570S/571S, 42LV570G/570S-ZB, 42LV571S-ZA



 The appearance of the MainBoard EAX64405401 is shown in the figure below:
EAX64405401
EAX64405401 can be used in TVs:
LG 32LV571S (Panel LC320EUD (SD)(F3)), LG 42LV571S ZA (Panel LC420EUF (SD) (A1)).
The appearance of the power supply
Main features of the device LG 42LV571S:
Installed matrix (LED-panel) LC420EUF (SD) (A1).
To power the backlight LEDs, a converter is used, combined with a power supply.
The necessary supply voltages for all nodes of the LG 42LV571S TV are generated by the EAX62865401 power module or its analogs using FAN7930B (PFC), 3BR4765JZ (Standby), L6599AD (PWM Resonant) microcircuits.
MainBoard - the main board (motherboard) is an EAX64405401 module using LGE35230, K4B2G1646C-HCKO, TH58DVG4S0ETA20, NTP7400L, F0514A, M24C16 and other chips.
The TDFR-G256D tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC420EUF-SDA1
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 10%), Hard coating (3H)
Brightness: 450 cd / m²
Contrast Ratio: 1600: 1
Display Colors: 1.06B (8-bit + FRC), CIE1931 72%
Response Time: 5 (G to G); 8 (MPRT)
Frequency: 120Hz
Lamp Type: WLED Without Driver
Signal Interface: LVDS (4 ch, 10-bit), 92 pins
Voltage: 12.0V
Posted By: FRANK at 06:16
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