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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Sunday 23 February 2020

REPAIR / SERVICING TV LG 37LD420

Technical description and composition of the LG 37LD420 TV, panel type and applicable modules. The composition of the modules.
LG
Model: 37LD420 ZA
Chassis / Version: LD01B
Panel: T370HW03 V.B
T-CON: T370HW03 VB CTRL BD; AUO-12401 432WP
Inverter (backlight): integrated into PSU
PWM Inverter: BD9270F
Trans Inverter: LIF32-100L GH130
Power Supply (PSU): EAX61124202 / 2
PWM Power: STR-W6053N, HS01G (PFC)
MOSFET Power: 10NM60N
MainBoard: EAX61354204 (0)
IC MainBoard: CPU: LGE107DC, FLASH NAND: H27U1G8F2BTR, DDR3 SDRAM: Audio amp: NTR-7100, 32K FLASH, Gamma: 9668E, Dc / Dc: 17113E, Eeprom: 24C16WR, SPI Flash: 25Q80
Tuner: TDTJ-S001D
Control: AKB72915207
Specifications 37LD420
LG 37LD420
General recommendations for repairing TV LCD
Repair of the LG 37LD420 ZA TV should begin with a fault diagnosis, which involves a careful examination of the external and internal elements of the device. A visible physical change in some components can sometimes suggest a further troubleshooting direction. If charred resistors, swollen electrolytic or cermet capacitors, ring cracks in the soldered terminals of transformers or heating elements are detected, it is advisable to establish the causes and consequences of the malfunction that has arisen, as well as to check the connected elements and assemblies.
If the TV does not turn on, no indicators on its front panel are lit or blinking. Also, if the TV does not respond to the remote control and buttons, does not make any sounds or any signs of operability when turned on, there is a certain chance that the EAX61124202 / 2 power supply module is defective and needs repair. Sometimes with similar manifestations a problem can only occur in the absence of standby power. It is advisable to start the troubleshooting of the power supply module by checking the state of the electrolytic capacitors of the rectifier filters and the mains fuse. Defective capacitors should be replaced. If the mains fuse is broken, it is necessary to check first of all the power semiconductor elements - rectifier diodes and transistors, which are often found in such a state of breakdown.
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 reason may be a malfunction of the PWM controller chip STR-W6053N, HS01G (PFC), which can only be checked by replacing it with a new or obviously working one.
If the LG 37LD420 does not have an image, there is sound and the channels are switched, there is a possibility of a malfunction of the display backlight, or their power converter - inverter. Sometimes when you turn on the image appears and disappears immediately. In such cases, it is necessary to check the electrolytic capacitors of the power filter of the inverter itself, including in the secondary rectifier of the main PSU. It is necessary to take into account that in cases of inverter protection shutdown (in order to be able to diagnose) there is a risk of failure of the inverter power elements and take special care. After carrying out repairs, the protection circuit must be restored for further safe operation of the TV.
On the EAX61354204 (0) motherboard, in case of a malfunction, you should first check the performance of all the stabilizers and power converters of the microcircuits, and also, if necessary, update the software (software). In some cases, it is necessary to check or replace (if necessary) the elements of the MainBoard board - CPU: LGE107DC, FLASH NAND: H27U1G8F2BTR, DDR3 SDRAM: H5T01G63BFR, Audio amp: NTR-7100, 32K FLASH, Gamma: 9668E, Dc / Dc: 17113E, Eeprom: 24C16WR, SPI Flash: 25Q80BVCIG. In cases where the BGA processor is used, its malfunction is usually detected by the local heating method.
The TDTJ-S001D tuner malfunction is established after checking the software and all supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
Once again, we remind TV users: you should not make attempts to repair it yourself without the appropriate knowledge, experience and the necessary qualifications! Trust the repair only to professionals with sufficient experience in the field of electronic equipment repair.
schematic diagram ------------->  LG 37LD420 LD01B 37LD420, 37LD420N, 37LD420-ZA, 37LD420N-ZA, 37LD428, 37LD420C, 37LD428-ZA, 37LD420C-ZA


 The appearance of the MainBoard EAX61354204 is shown in the figure below:
EAX61354204
EAX61354204 can be used in TVs:
LG 32LD345 (Panel LC320WXE-SCA1), LG 37LD450 (Panel LC370WUG (SC)(A1)), LG 42LD455-ZA (Panel LC420WUG), LG 32LD550 (Panel LK315D3LA57), LG 42LD450 ZA (Panel LC420WUG (SC)(A1)), LG LG32LD350 32LD350 (Panel T315HW04 V.8), LG 42LD420 ZA (Panel LC420WUG (SC)(A1)), LG 37LD420 ZA (Panel T370HW03 V.B), LG 32LD420 ZA (Panel LC320WUG (SC)(A1)), LG 32LD555 ZC (Panel LC320WUG (SC)(A1)), LG 26LD355-ZA (Panel T260XW04 V.3), LG 37LD425 ZA (Panel T370HW03 V.B), LG 32LD425 (Panel LC320WUG (SC)(A1)), LG 32LD340 32LD340-ZA.BRUWLJU (Panel LC320WXE (SC)(A1)).
PSU Advanced
The 37LD420 model uses the EAX61124202 / 2 power supply unit using the PFC (Power Factor Correction) node - an active filter of the highest harmonics of the current consumption. In fact, it is a step-up converter based on the HS01G PWM controller, which eliminates the charge current of the electrolytic capacitor of the rectifier filter directly from the network through open diodes when its charging current is determined by its reactance.
As a result of the operation of the converter, the envelope of the high-frequency pulses of the input current of the converter will repeat the shape and phase of the input voltage. The health of the PFC node can be indirectly judged by the presence of an increased constant voltage (about + 380V) on the capacitor of the rectifier network in operating mode.
The appearance of the power supply
Main features of the device LG 37LD420:
Installed matrix (LCD-panel) T370HW03 V.B.
The matrix control uses the Timing Controller (T-CON) T370HW03.
To power the backlight, a converter is used, combined with the power supply, controlled by the BD9270F PWM controller. The transformer LIF32-100L GH130 is installed in the inverter converter.
The necessary supply voltages for all nodes of the LG 37LD420 TV are generated by the EAX61124202 power module or its analogs using STR-W6053N, HS01G (PFC) microcircuits and 10NM60N type power switches.
MainBoard - the main board (motherboard) is an EAX61354204 module, using CPU chips: LGE107DC, FLASH NAND: H27U1G8F2BTR, DDR3 SDRAM: H5T01G63BFR, Audio amp: NTR-7100, 32K FLASH, Gamma: 9668E, Dc3E11, Dc / Dc: 17 Eeprom: 24C16WR, SPI Flash: 25Q80BVCIG and others.
The TDTJ-S001D tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: AUO
Model: T370HW03 VB
Type: a-Si TFT-LCD, Panel
Diagonal size: 37 inch
Resolution: 1920x1080, FHD
Display Mode: AMVA3, Normally Black, Transmissive
Active Area: 819.36x460.89 mm
Surface: Antiglare (Haze 11%), Hard coating (3H)
Brightness: 450 cd / m²
Contrast Ratio: 5000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 6.5 (G to G)
Frequency: 60Hz
Lamp Type: 10 pcs CCFL Embedded (Balance board)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V
Posted By: FRANK at 07:40
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