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 75SK8100

Technical description and composition of the LG 75SK8100 TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 75SK8100 75SK8100PLA
Chassis / Version: EAX67895403
Panel: LC750EQF (FL) (M2)
LED backlight: 6922L-0245A
T-CON: 6870C-0767A
LED driver (backlight): integrated into PSU
Power Supply (PSU): EAX67884601 LGP75-18UL12
PWM Power: PFC, PWM
MainBoard: EAX67895403 (1.0)
IC MainBoard: CPU, eMMC, DRAM, AUDIO, DC / DC
Tuner: DVB-T2 & SAT
Control: EBR83592301, LGSBWAC72
Specifications 75SK8100
LG 75SK8100
General repair guidelines for TV LCD LED
Possible malfunctions
- LG 75SK8100 TV does not turn on. There are no signs of operability. The indicators on the front panel do not light up and do not blink, the TV does not respond to the control buttons.
Most often, with such manifestations, the main power supply module EAX67884601 is found to be faulty. It is necessary to measure its output supply voltages, and in case of their absence, check the serviceability of the power switches of the converters and rectifier diodes for the probability of breakdown in PN semiconductor junctions.
In the event of breakdowns in the secondary circuits of the converter, it can usually fail in short circuit mode, and in the event of a short circuit in the power elements of the primary circuit, the mains fuse or current sensor at the source of the key most often breaks.
Breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback (OOS) stabilization circuits. PWM controllers (PWM), if they do not have visible damage to the case and open short circuit between the terminals, are usually checked by replacement.
- There is no image, but there is sound and all the other functions of the TV work. The image sometimes for a second appears immediately after turning on and disappears.
In such cases, the most likely malfunction of the LED backlight elements. The reason may be the breakage of the LEDs, in the stabilization of their power supply, or in the violation of the contact connections of the thong connectors,
To check the LED lines for breaks without disassembling the panel, for example, a current source will help. It is impossible to open series-connected PN junctions with a simple multimeter, a voltage of the order of several tens of volts is required.
- 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 EAX67895403 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). If it is not possible to replace the MB (SSB) card, you need to check the health of its elements - CPU, eMMC, DRAM, AUDIO, DC / DC. Defective components should be replaced.
If there is no reception of television channels, but the TV is working properly from external devices, first of all, check the voltage of the DVB-T2 & SAT 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 75SK8100 TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!




The appearance of the MainBoard EAX67895403 is shown in the figure below:
EAX67895403
The appearance of the power supply
Main features of the device LG 75SK8100:
Installed matrix (LED-panel) LC750EQF (FL) (M2).
The matrix control uses the Timing Controller (T-CON) 6870C-0767A.
To power the backlight LEDs, a converter is used, combined with a power supply.
The formation of the necessary supply voltages for all nodes of the LG 75SK8100 TV is carried out by the EAX67884601 power module, or its analogs using PFC, PWM chips.
MainBoard - the main board (motherboard) is an EAX67895403 module, using CPU, eMMC, DRAM, AUDIO, DC / DC, and others.
The DVB-T2 & SAT tuner allows you to receive television programs and tune to channels.
Posted By: FRANK at 08:40
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