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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Monday, 24 February 2020

REPAIR / SERVICING TV LG 42LA690V

Technical description and composition of the LG 42LA690V TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 42LA690V
Chassis / Version: LD33B
Panel: LC420EUH (PF) (P1)
LED backlight: Edge LED 6922L-0072A
LED driver (backlight): integrated into PSU
PWM LED driver: IW7011, R5F100BCAFP
MOSFET LED driver: TK15A20D
Power Supply (PSU): EAX64905701 (2.5) EAY62810901 LGP4247-13LPB
PWM Power: ICE3BR4765JZ (Stb), R2A20133D (PFC), SSC9527S
MOSFET Power: 13NM60N, 10NM60N
MainBoard: EAX64797004 (1.1) EBR76823174
IC MainBoard: LGE2122 1402-BTAN, NAND: 3DAI8 JW857, H5TQ4G63AFR
Tuner: TDSQ-G501 (B) EBL6120403
Control: IR: EBR76405602, WiFi: EAT61813901 TWFM-B006D
Specifications 42LA690V
LG 42LA690V
General repair guidelines for TV LCD LED
Possible malfunctions
- The LG 42LA690V TV does not turn on and does not show any signs of turning on, it does not respond to the control buttons or to the remote control.
With such manifestations, the EAX64905701 power supply module usually fails. It is necessary to measure its output voltages and, if they are absent, check the power switches (13NM60N, 10NM60N) and rectifier diodes for the probability of short circuit in the converters.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during short circuit in the elements of the primary circuit, the mains fuse usually 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) ICE3BR4765JZ (Stb), R2A20133D (PFC), SSC9527S, 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, there is sound, it responds to the remote control, the channels are switched. In some cases, the image appears when you turn on and immediately disappears.
In most of these cases, a malfunction is detected in the nodes and backlight elements of the LED panel. More often the reason for this is the breakdown of the LEDs, or poor contact in the connectors of the strips, less often the LED driver may be malfunctioning.
When diagnosing, it is necessary to take into account that it is impossible to check the open in the chain of LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally, a current source. By opening the panel, each LED can be checked separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect probes in the forward direction to it. In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as a health indicator. 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, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the EAX64797004 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). In cases of complex repairs of MB (SSB) and in the presence of the necessary skills and equipment, sometimes it may be necessary to replace its chips LGE2122 1402-BTAN, NAND: 3DAI8 JW857, H5TQ4G63AFR and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
In the absence of tuning to the channels of on-air or cable television, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltage at the terminals of the TDSQ-G501 (B) EBL6120403 tuner. It is also necessary to check the presence of pulses of data exchange between the tuner and the processor via the I2C bus using an oscilloscope.
Attention! For users and owners of 42LA690V TVs who do not have the appropriate qualifications, knowledge and experience, we categorically do not recommend attempting self-repair in order to avoid negative consequences that could lead to complete non-repairability of the device.
Schematic diagram ------------>  LG 42LA690V Chassis LD33B.

 The appearance of the MainBoard EAX64797004 is shown in the figure below:
EAX64797004
EAX64797004 can be used in TVs:
LG 42LA660S ZA 42LA660V (Panel LC420EUH (PF)(P1) 120 Hz), LG 32LA620V (Panel LC320DUE (SF)(U1)), LG 42LN570V (Panel LC420DUE (SF)(R3)), LG 50LA620V ZA (Panel LC500DUE (SF)(U1)), LG 32LN575S (Panel LC320DUE (SF)(R1)), LG 42LA669V 42LA669V-ZE.BRUZLJU (Panel LC420EUH (PF)(P1)).
The appearance of the power supply
Main features of the device LG 42LA690V:
Installed matrix (LED-panel) LC420EUH (PF) (P1).
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by the IW7011, R5F100BCAFP PWM controller. As the power elements of the LED driver, keys of the TK15A20D type are used.
The necessary supply voltages for all nodes of the LG 42LA690V TV are generated by the EAX64905701 power module or its analogs using ICE3BR4765JZ (Stb), R2A20133D (PFC), SSC9527S microcircuits and 13NM60N, 10NM60N type power switches.
MainBoard - the main board (motherboard) is an EAX64797004 module using LGE2122 1402-BTAN chips, NAND: 3DAI8 JW857, H5TQ4G63AFR and others.
Tuner TDSQ-G501 (B) EBL6120403 provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: LG Display
Model: LC420EUH-PFP1
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 927.94x521.96 mm
Surface: Antiglare (Haze 1%), Hard coating (2H)
Brightness: 400 cd / m²
Contrast Ratio: 1400: 1
Display Colors: 16.7M / 1.06B (8-bit / 8-bit + Dithering), CIE1931 68%
Response Time: 8/10 (Tr / Td)
Frequency: 120Hz
Lamp Type: WLED Without Driver
Signal Interface: EPI, 100 pins
Voltage: 12.0V

Posted By: FRANK at 03:10
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