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........ . . . . . .....
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Monday, 24 February 2020

REPAIR / SERVICING TV LG 42LA643V

Technical description and composition of the LG 42LA643V TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 42LA643V
Chassis / Version: LD33B
Panel: LC420EUN (SF) (F3)
LED backlight: 6922L-0062A 42 V13 Edge Rev1.0 2 6020L-0001C
T-CON: 6870C-0444A LC470DUE-SFR1
LED driver (backlight): 3PHCC20006C-H PCLF-D202 C REV0.3 6917L-0119C
Power Supply (PSU): EAX64908001 (1.9) LGP3942-13P
PWM Power: R2A20133DSP (PFC), L6544AD, FSD106LG
MOSFET Power: MBR10U100CT, TK8P60V
MainBoard: EAX64891306 (1.1) EBR76922718 SAA36254751 SAA36340623
IC MainBoard: CPU: LGE2121-MS, DRAM: H5TQ2G630FR, NAND Flash: SAA36254746F VER 03.13.72, SPI Flash: 25Q80, SOUND: STA3808WF
Tuner: TDSQ-G601D (B)
Control: IR: EBR76405702 LA6400
Specifications 42LA643V
LG 42LA643V
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The LG 42LA643V 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, the EAX64908001 power supply module usually fails. It is necessary to measure its output voltages, and if they are absent (full or partial), you should check the health of the power switches (MBR10U100CT, TK8P60V) of the converters and rectifier diodes for a possible short circuit.
In case of breakdowns in the secondary circuits, the converter, as a rule, can emergency work in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse usually breaks.
Mos-Fet power switches, used in switching power supplies, sometimes fail due to a malfunction of any other elements that can put it out of operation in key mode, or create an excess of the maximum permissible parameters of the switch. These can be elements supplying the PWM controller, frequency-setting or damping circuits, or negative feedback elements in the stabilization circuit. PWM controllers R2A20133DSP (PFC), L6544AD, FSD106LG, in the absence of visible damage or explicit short-circuit between the terminals, are checked by replacing with new, or obviously working.
- 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.
As a rule, in such cases there is no display backlight. The reason can be found in the failure of the LEDs, in the violation of the contact connections of the LED strips, or in the provision of their power (LED driver).
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 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 turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the EAX64891306 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). Sophisticated MB board repair (SSB) is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the CPU elements: LGE2121-MS, DRAM: H5TQ2G630FR, NAND Flash: SAA36254746F VER 03.13.72, SPI Flash: 25Q80, SOUND: STA3808WF. BGA chip malfunctions are usually easy to detect by warming up.
Before replacing the TDSQ-G601D (B) tuner, if there is no channel tuning, 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
Attention TV owners! Attempts at self-repair of LG 42LA643V are not recommended by the manufacturer and can lead to serious negative consequences!
Schematic diagram ------------>  LG 42LA643V Chassis .

FIRMWARE  SPI FLASH ------------> LG 42LA643V LD33B, Main: EAX64891306 (1.1) EBR76922718 SAA36254751 SAA36340623, Panel: LC420EUN (SF)(F3)




 The appearance of the MainBoard EAX64891306 is shown in the figure below:
EAX64891306
EAX64891306 can be used in TVs:
LG 32LN540V (Panel LC320DUE (SF)(R1)), LG 42LN542V-ZD (Panel LC420DUE SFR3), LG 32LN541V (Panel LC320DUE (SF)(R1)), LG 42LA615V (Panel LC420DUE (SF)(U2) ), LG 32LA615V (Panel LC320DUE (SF)(U2)), LG 42LN540V (Panel LC420DUE (SF)(R1)), LG 42LN541V (Panel LC420DUE (SF)(R1)), LG 47LN540V (Panel LC470DUE (SF)(R1)), LG 32LB530U ZA (Panel LC320DXE (SG)(R1)), LG 39LN540V (Panel HC390DUN-VCFP1-11XX), LG 32LA643V (Panel LC320EUN (SF)(F1)), LG 32LN542V (Panel LC320DUE SF R1), LG 47LA615V (Panel LC470DUE (SF)(U2)), LG 47LA643V ZB (Panel LC470EUN (SF)(F2)), LG 32LN541U ZB (Panel HC320DXN-VHFP1 - 21XX / HC320DXN-VHFPA - 21XX), LG 32LN536U (Panel NC320DXN (SA)(P1)), LG 37LN541U (Panel LC370DXE (SF)(R1)).
The appearance of the power supply
Main features of the device LG 42LA643V:
Installed matrix (LED panel) LC420EUN (SF) (F3).
The matrix control uses the Timing Controller (T-CON) 6870C-0444A.
The LED driver 3PHCC20006C-H is used to power the backlight LEDs.
The necessary supply voltages for all nodes of the LG 42LA643V TV are generated by the EAX64908001 power module or its analogs using R2A20133DSP (PFC), L6544AD, FSD106LG microchips and power switches of the MBR10U100CT, TK8P60V type.
MainBoard - the main board (motherboard) is an EAX64891306 module using CPU chips: LGE2121-MS, DRAM: H5TQ2G630FR, NAND Flash: SAA36254746F VER 03.13.72, SPI Flash: 25Q80, SOUND: STA3808WF and others.
The TDSQ-G601D (B) tuner allows you to receive television programs and tune to channels.
Additional technical information about the panel:
Brand: LG Display
Model: LC420EUN-SFF3
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: IPS, Normally Black, Transmissive
Active Area: 927.94x521.96 mm
Surface: Antiglare (Haze 1%), Hard coating (2H)
Brightness: 350 cd / m²
Contrast Ratio: 1400: 1
Display Colors: 16.7M (8-bit), CIE1931 68%
Response Time: 6 (G to G)
Frequency: 60Hz
Lamp Type: WLED Embedded (LED Driver)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V



Posted By: FRANK at 02:43
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