Master Electronics Repair !

Welcome to Master Electronics Repair! website.Here you will find:Service Modes, Circuit Diagrams,Service manuals, Firmware Update procedure, Disassemble procedure, Universal remote control setup codes, Troubleshooting, Diagnosing, Measuring, and more.... of many of LCD/LED TV/Displays,others various electronic apparates,trough many technical notes and tips/tricks to help repairing/fixing Troubles/ faults,for electrical technicians.This site helps you to save the Earth from electronic waste!

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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Friday 1 February 2019

LG42LE5500 - LED BACKLIGHTS 1080PDIRECT VIEW LCDTV – SMPS (POWER SUPPLY) BOARD [EAY60803101] TROUBLESHOOTING-REPAIR

LG42LE5500 - LED Backlights 1080PDirect View LCDTV – SMPS (Power supply) board [EAY60803101] troubleshooting-repair

How to troubleshoot and repair Power board of LG42LE5500 LED TV

Part number: EAY60803101

POWER SUPPLY SECTION

This switch mode power supply develops Stand By 3.5V at all times when AC is applied.

At power on, it develops 12V and 20V for the Main board.

It develops 120V for the LED Backlights

This power supply draws less than 1 watt during stand by mode. The fuse F101 and F103 reads 7.6V (from hot ground) during this time.

When the controller chip receives the PWR-ON command 3.36V via P201 Pin 1, the primary section increases its current supplying ability. Both Primary fuses F101 and F103 now read a little more than 395V.

T102 delivers AC to D206 which develops the 120V for the LED backlights.

P201 Connector: (To Main Board)

12V (11.43V) is routed out P201 pins 17, 19 and 21 and 20V (21.27V) is routed out P201 pins 2, 3 and 4.

P204 Connector: (To Panel LEDs)

120V is routed out P204 pins 1 and 12.

P205 Connector: (To Panel LEDs)

120V is routed out P205 pins 1 and 12

Power Supply Start Up Sequence Click on the pictures to magnify

42LE5500 Television Turn On Commands Circuit Drawing.

Power Supply Board Low Voltage Test

AC Should not be applied at any time while adding jumpers or While unplugging connectors as damage to the circuit Board may occur.
a) When AC is applied, the SMPS “MUST” be producing STBY 3.5V on pins 9, 10, 11 or 12 of P201.
If 3.5V Standby is not being generated, the SMPS is defective and must be replaced. There is no need to continue with the next test. But, make sure AC is arriving at the connector SK101.
(b) Unplug P8000 on the Main Board to make insertion of the Jumpers easier. Use P700 Side to insert resistors.

No Back-light during this test

Add a jumper between (3.5V STBY) pin 7, 8, 9 or 10 and Pin 1 (PWR_ON). Apply AC.
This will turn on the power supply, relays will click.
a) Check that the 24V and 12V power supplies are turned on,
* P201 (12V pins 17, 19 and 21)
* P201 (24V pins 2, 3 and 4)
* P204 and P205 (120V pins 1 and 12) to the Panel. (Or check D206 + lead)
(2) Remove the AC power.

Power Supply Board Back-light Test

Continue if the 1st test was OK.
Leave original jumper in place.
(3) Add another jumper between (STBY_3.5V)
pin 9, 10, 11 or 12 and Pin 18 (INV_On).
(4) Apply AC Power. (Simulating a Power and Back-light On command.)

Back-lights Normal

a) If normal, the backlights should turn on.

SMPS OK, Inverter OK.

Backlights Abnormal:

a) Recheck all connections.

b) Confirm the INV On/Off line pulling up to at least 3V.

c) Check the connections to the Panel.

If the Inverter On command is pulling up to 3V and the 120V is being generated from D206 + lead, See the Inverter Section of the Power Supply for additional checks.

Note: If either P204 or P205 is disconnected, the backlights will come on, but shut off in 4 seconds.

REMOVE AC POWER