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 26 February 2020

REPAIR / SERVICING TV LG 42LD555-ZC

Technical description and composition of the LG 42LD555-ZC TV, panel type and applicable modules. The composition of the modules.
LG
Model: 42LD555-ZC
Chassis / Version: LD01B
Panel: LC420WUG (SC) (A1)
Inverter (backlight): integrated into PSU
PWM Inverter: BD9270F (24 pin)
Power Supply (PSU): EAX61124201 16 Ver1.3
PWM Power: STR-W6053N, HS01G (PFC)
MOSFET Power: 13NM60N, 2SK3868
MainBoard: EAX63329201
IC MainBoard: SPI Flash: W25Q80BVSIG; EEPROM: 24C16WP
Tuner: TDTJ-S001D
Control: AKB72914209
Specifications 42LD555
LG 42LD555-ZC
General recommendations for repairing TV LCD
It is recommended that you start troubleshooting diagnostics and repairing LGs with the LD01B chassis, as well as other electronic devices, with an external inspection of the external and internal elements. Often, by the external signs and nature of the damage to the elements, it becomes possible to draw some conclusions and determine a further algorithm for finding a defect before making the necessary measurements at control points. In some cases, faulty elements can be seen with the naked eye, for example, charred resistors or swollen metal-ceramic capacitors, or electrolytic in rectifier filters. Ring cracks formed in the soldered terminals of transformers or heating elements of the circuit are also frequent sources of many malfunctions with a variety of external manifestations.
Sometimes the LG 42LD555-ZC TV just does not turn on. No control lights on the front panel are lit or blinking, the TV does not respond to the remote control and does not make any sounds or any signs of life when turned on. The most likely cause of the malfunction is the failure of the EAX61124201 16 Ver1.3 Common Power Module. If it is working properly, you need to check the processor batteries on the SSB (Main Board). When repairing the power supply, it is advisable to start the diagnostics by checking the mains fuse and the electrolytic capacitors of the filters of the converter secondary rectifiers. In the event of a fuse breaking, the reason should be sought in the power semiconductor elements of the pulse converter of the main power supply. First of all, it is necessary to check the diodes of the bridge of the rectifier of the mains voltage and the power switch (s) of the converter.
Power switches in pulsed power supplies (SMPS) fail extremely rarely for no reason and, if they are broken, it is necessary to look for a malfunction in the stabilization circuits by checking electrolytic capacitors, semiconductor devices, and resistors in the primary circuit. The cause may be a malfunction of the PWM controller chip, which can only be checked by replacing it with a new or obviously working one.
If the LG 42LD555-ZC has no image, but there is sound and the TV is controlled from the remote control, a malfunction in the display backlight nodes is likely. The lamps or the power converter - inverter may be faulty. Often in such cases, when you turn on the TV, an image appears and immediately disappears. First of all, it is necessary to verify the operability of the electrolytic capacitors of the rectifier filter supplying the inverter, and check the LCD lamps by connecting external and obviously serviceable for diagnosis to the connectors. If in diagnosing a malfunction, it is necessary to disable the inverter protection, there is a risk of failure of the power elements of the inverter, and special care is required during work, and after their completion it is necessary to restore the protection circuits for further safe operation of the TV by the owner in normal mode.
If the EAX63329201 motherboard is faulty, first of all it is necessary to check all the linear stabilizers or power converters of its chips, and also, if necessary, update the software. Sometimes you can check the health of MB only by replacement.
We recommend the owners of the 42LD555-ZC TV for repair only to qualified specialists with experience! Self-repair attempts without the appropriate knowledge and skills can lead to serious negative consequences!
schematic diagram ------------>  LG 42LD550, 42LD558, 42LD550-ZC, 42LD558-ZC, 42LD551, 42LD559, 42LD551-ZA, 42LD559-ZA, 42LD550N, 42LD550N-ZC Chassis LD01B.


PSU schematic diagram ------------>  LGP42-10LF EAX61124201 EAY60869402 Power supply

 The appearance of the MainBoard EAX63329201 is shown in the figure below:
EAX63329201
EAX63329201 can be used in TVs:
LG 42LD555-ZC (Panel LC420WUG (SC)(A1)), LG 32LD335 ZA (Panel T315XW03 V.1), LG 37LD425 ZA (Panel T370HW03 V.B), LG 42LD425 (Panel LC420WUG (SC)(A1)), LG 26LD335 26LD335-ZA.BRUDLJU (Panel T260XW04 V.3).
PSU Advanced
On the 42LD555-ZC TV, the EAX61124201 power module is installed using the PFC (Power Factor Correction) scheme acting as an active filter to eliminate the higher harmonic components of the current consumption. The step-up converter based on the HS01G PWM controller does not allow the input rectifier filter's electrolytic capacitor to be connected to the network directly through open diodes when the charge current is determined by its reactance (of the order of 15-30 ohms at a frequency of 50 Hz). 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 42LD555-ZC:
Installed matrix (LCD panel) LC420WUG (SC) (A1).
To power the backlight, a converter is used, combined with a power supply, controlled by a BD9270F PWM controller (24 pin).
The necessary supply voltages for all nodes of the LG 42LD555-ZC TV are generated by the EAX61124201 power supply module or its analogs using STR-W6053N, HS01G (PFC) microcircuits and 13NM60N, 2SK3868 power switches.
MainBoard - the main board (motherboard) is an EAX63329201 module using SPI Flash chips: W25Q80BVSIG; EEPROM: 24C16WP and others.
The TDTJ-S001D tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC420WUG-SCA1
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: 500 cd / m²
Contrast Ratio: 1450: 1
Display Colors: 16.7M / 1.06B (8-bit / 8-bit + FRC), CIE1931 72%
Response Time: 8/10 (Tr / Td)
Frequency: 60Hz
Lamp Type: 16 pcs EEFL Without Driver
Signal Interface: Mini LVDS, 60 pins
Voltage: 12.0V
Posted By: FRANK at 08:13
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