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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Thursday 27 February 2020

REPAIR / SERVICING TV LG 42LM340T

Technical description and composition of the LG 42LM340T TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 42LM340T
Chassis / Version: LD21B / LC21B
Panel: LC420DUN (SE) (U3) // LC420DUN (SE) (U2)
LED backlight: 6916L-1028A, 6916L-1029A
T-CON: T-con 6870C-0401C
LED driver (backlight): KLS-E420DRPHF02C, 6917L-0095C
PWM LED driver: BD9285F
MOSFET LED driver: AOD482, STC2073
Power Supply (PSU): EAX64604501 (1.5) LGP32M-12P
PWM Power: L6599AD (PWM Resonant), FSL106HR (Standby DIP-8), HS01G (PFC)
MOSFET Power: MDF11N60, STD10NM60N
MainBoard: EAX64909901 (1.0)
IC MainBoard: LGE2111A-T8, NAND FLASH: H27U1G8F2BTR / BC - 1 Gbit (128M x 8 bit), SPI: W25Q80, EEPROM: 24C256, AUDIO: STA380BWE
Tuner: TDSN-G301D
Control: IR: EBR74986702, LM35-55, MB32B00, 1BF-3010B
Specifications 42LM340T
LG 42LM340T
General repair guidelines for TV LCD LED
Diagnostics of malfunctions and repairs LG 42LM340T, as well as other electronic devices, it is recommended to start with an external examination of the external and internal elements. Specific external damage to some elements can sometimes indicate further actions to determine the malfunction of the TV and localize the defect before the necessary measurements are taken. Electrolytic capacitors of filters with a swollen casing, as well as ring cracks formed in the soldered leads of heating elements, or a layer of coal on burnt resistors sometimes tell the repairman the causes of the malfunction and possible consequences.
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 LGP32-12P power supply module is defective and needs repair. Sometimes with similar manifestations a problem can only occur in the absence of processor power, which is typical for certain LG models. In the general case, first of all, it is necessary to check the electrolytic capacitors of the secondary rectifier filters and the fuse at the input of the network. If it is cut off, then it is necessary to check the diodes of the rectifier bridge and the key transistor of the converter for a breakdown of the PN junctions, which can either be on a separate radiator or integrated with a PWM controller in a common chip. Possible options.
As a rule, the keys in switching power supplies (SMPS) are reliable enough and rarely fail for no reason to be looked for by checking other components of the circuit - electrolytic capacitors, resistors and semiconductor elements of the primary circuit. The PWM chip is verified by replacing it with a known good one.
If the LG 42LM340T does not have an image, there is sound and the channels are switched, there is a possibility of a malfunction in the backlight LED circuit of the LC420DUN (SE) (U3) panel, or their power converter - LED driver. 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 LED driver itself, including in the secondary rectifier of the main PSU.
Often there is a need for disassembling the panel to check the health of the LEDs, as well as contact connections in the connectors and soldering.
A break in the line of LEDs connected in series cannot be detected with a multimeter or tester without disassembling the panel. To open all the transitions, several tens of volts are needed, and it is best to use a current source for such purposes.
Diagnosis and repair of the EAX64909901 motherboard (1.0) is carried out by checking the performance of the stabilizers or power converters of the module chips. In some cases, a software update is required.
In some cases, it is necessary to check or replace (if necessary) the elements of the MB (SSB) board - LGE2111A-T8, NAND FLASH: H27U1G8F2BTR / BC - 1 Gbit (128M x 8 bits), SPI: W25Q80, EEPROM: 24C256, AUDIO: STA380BWE . In cases where the BGA processor is used, its malfunction is usually detected by the local heating method.
The malfunction of the TDSN-G301D tuner is established after checking the software and all the supply voltages at its terminals.
Attention to the owners! Attempts to self-repair the LG 42LM340T TV are not recommended by the manufacturer and can lead to serious negative consequences!
SCHEMATIC DIAGRAM --------->  LG_CHASSIS : LD21C, MODEL : 42LM3400/340S/340T, 42LM3400/340S/340T-ZA SERVICE MANUAL.


PSU SCHEMATIC DIAGRAM --------->  LG EAX64604501 (1.5) LGP32M-12P-3 Power supply



 The appearance of the MainBoard EAX64909901 is shown in the figure below:
EAX64909901
EAX64909901 can be used on TVs:
LG 42LM580T-ZA (Panel LC420EUE (SE)(F1)), LG 42LM340T (Panel LC420DUN (SE)(U3)), LG 32LM580T (Panel LC320EUN (SE)(F3)), LG 42LM585T ZD (Panel LC420EUE (SE)(F1)), LG 42LM615T (Panel LC420EUE (SE)(F1)), LG 42LS560T 42LS560T-ZC (Panel T420HVN01.1).
The appearance of the power supply
Main features of the device LG 42LM340T:
Installed matrix (LED-panel) LC420DUN (SE) (U3) or LC420DUN (SE) (U2).
The matrix control uses the T-con Timing Controller (T-CON).
To power the backlight LEDs, the KLS-E420DRPHF02C LED driver is used, controlled by the BD9285F PWM controller. As power elements of the LED driver, keys of the type AOD482, STC2073 are used.
The necessary supply voltages for all nodes of the LG 42LM340T TV are generated by the EAX64604501 power supply module or its analogs using L6599AD (PWM Resonant), FSL106HR (Standby DIP-8), HS01G (PFC) microcircuits and MDF11N60, STD10NM60N type power switches.
MainBoard - the main board (motherboard) is an EAX64909901 module using LGE2111A-T8 chips, NAND FLASH: H27U1G8F2BTR / BC - 1 Gbit (128M x 8 bits), SPI: W25Q80, EEPROM: 24C256, AUDIO: STA380BWE and others.
The TDSN-G301D tuner provides television reception and channel tuning.
Information from an alternative source:
LG 42LM340T-ZA Chassis LD21B / LC21B
Panel Type (Matrix): LC420DUN (SE) (U2),
Motherboard: EAX64317404 (1.0), IC102- (sticker: SAA35916762 / Ver3.03.50 / SAA35948821 / Ver3.00.70), IC1201 = IC1201-2LG22x2, IC1401-25Q80BVSIG, AS324M, IC403-54319, IC2602-IC2420, IC2602-TC2442 IC104-4HA7, IC401-Z105NP, IC407-AP7173, IC3400-STA3808WE, Tuner: TDSN-G301D,
T-con: 32/37/42/47/55 FDH TM120 Ver 0.3 P / N: 6870C-0401C,
Invertor: KLS-E420DRPHF02 C REV: 0.5 6917L-0095C,
PSU: LGP32-12P EAX64604501 (1.5) PSLC-L251A, IC501-FSL106HR, IC601-L6599AD, IC101-ICE1HS01G, Q101-102-TK7P60V, Q603-MDF11N60
Remote control: AKB73655802
Additional technical information about the panel:
Brand: LG Display
Model: LC420DUN-SEU3
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: IPS, Normally Black, Transmissive
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 1%), Hard coating (2H)
Brightness: 300 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 07:05
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