LG 42LW4500-LB Need help with repair of PSU

[budm]

Re: LG 42LW4500-LB Need help with repair of PSU

the red marked one

That is MOV and it is NOT BAD, if it is activated the main fuse would have blown, it is for surge protection and it is not needed for the TV to function.
You should be able to read 230VAC between the two legs of that MOV because it is basically connected in parallel with that grey line filter cap which are connected between Line and Neutral.
You are looking at the wrong section.
There is NOTHING WRONG with that MOV!
http://www.mouser.com/ProductDetail/...IfAz8bpg%3D%3D

[budm]

Re: LG 42LW4500-LB Need help with repair of PSU

I do not understand which part is bad TH501, TH101?

[UndeadLuke]

Re: LG 42LW4500-LB Need help with repair of PSU

the red marked one

[UndeadLuke]

Re: LG 42LW4500-LB Need help with repair of PSU

That is MOV VA101 and it does not look like it is damaged, if it has been activated it would have blown the main AC fuse.

NTC TH501 is for the inrush current limiter for the STANDBY power supply section.
NTC TH101 is for the inrush current limiter for the MAIN power supply section.

All fuses are Okey main AC fuse is before this little b*tch I want to know what is it and what i can replace it iam agry of it as I sed I had no voltage after the part I will mark it on anotherpost I cant get no voltage on the relay so relay cant switch the voltage to diodes when you press power button it will imidietly turn off TV so i cant turn it on i think the marked part is definetly bad please tell me what it is and what can i replace with it :/

[UndeadLuke]

Re: LG 42LW4500-LB Need help with repair of PSU

How do you know the power supply is faulty? I would test the fuses first to see if theyre ok.

Its faulty .. I checked all fuses and they are OK .. all of them

[syaoran123]

Re: LG 42LW4500-LB Need help with repair of PSU

How do you know the power supply is faulty? I would test the fuses first to see if theyre ok.

[budm]

Re: LG 42LW4500-LB Need help with repair of PSU

The black thing right to geay capacitor on main is what because it got damaged and no fuse after this part

That is MOV VA101 and it does not look like it is damaged, if it has been activated it would have blown the main AC fuse.

NTC TH501 is for the inrush current limiter for the STANDBY power supply section.
NTC TH101 is for the inrush current limiter for the MAIN power supply section.

[budm]

Re: LG 42LW4500-LB Need help with repair of PSU

OK, so far you do have standby Voltage otherwise based on Post #1 "Hi guys today my TV stops working (it woudnt turn on only led shine so the power goes into it)"
Looking the board layout, you will not have any DCV between the two legs on any of the filter caps C612~C614 until you have > 2VDC at the 'PWR-ON' pin of the connector P201 to turn on the power relay RL101 to supply the 230VAC to the bridge rectifier BD101.
So check and see if you have DCV at 'PWR-ON' pin or not when the power switch is activated.

[UndeadLuke]

Re: LG 42LW4500-LB Need help with repair of PSU

The black thing right to geay capacitor on main is what because it got damaged and no fuse after this part

[UndeadLuke]

Re: LG 42LW4500-LB Need help with repair of PSU

Are these P/N printed on your board?
Is this the EXACT matched of your board?
LG EAY62169801 (EAX62865401/8)

Pictures provided by shopjimmy.

Yes

[UndeadLuke]

Re: LG 42LW4500-LB Need help with repair of PSU

Are these P/N printed on your board?
Is this the EXACT matched of your board?
LG EAY62169801 (EAX62865401/8)

Pictures provided by shopjimmy.

Yes

[budm]

Re: LG 42LW4500-LB Need help with repair of PSU

Are these P/N printed on your board?
Is this the EXACT matched of your board?
LG EAY62169801 (EAX62865401/8)

Pictures provided by shopjimmy.

[budm]

Re: LG 42LW4500-LB Need help with repair of PSU

BTW, I cannot read the PCBA P/N as printed on the barcode sticker to look for more info about the board.

[budm]

Re: LG 42LW4500-LB Need help with repair of PSU

We need clear straight shot pictures of the whole board.
There is a bridge rectifier (4-pin black device) mounted on the heatsink, you need to check the ACV between the two inner legs, it should have 230VAC between those two legs.
https://www.badcaps.net/forum/attach...8&d=1479570017

[UndeadLuke]

Re: LG 42LW4500-LB Need help with repair of PSU

https://www.badcaps.net/forum/attach...7&d=1479570017

So the fuse to left of the line filter cap (grey cap) is good for sure?
Are you getting 230VAC between the two legs of that grey cap?

Yes 250VAC on gray cap on right side of it its some type of varistor or part (i dont know what it is and which one i need to replace) this part has voltage on + but if you try + and - no voltage everything after that it has no or bad voltage in miliamperes

[budm]

Re: LG 42LW4500-LB Need help with repair of PSU

https://www.badcaps.net/forum/attach...7&d=1479570017

So the fuse to left of the line filter cap (grey cap) is good for sure?
Are you getting 230VAC between the two legs of that grey cap?

[UndeadLuke]

Re: LG 42LW4500-LB Need help with repair of PSU

Okey guys So I make big progresws today I check the big capacitors and no voltage on them the voltage stops on part INR or LNR next to main gray CAP so this part is definitly damaged does anyone know which one i need to replace ? it looks like Varistor but i dont know nothing about it

[dick_barton]

Re: LG 42LW4500-LB Need help with repair of PSU

To start off, what is the DC voltage across those capacitors. See post #11

[UndeadLuke]

Re: LG 42LW4500-LB Need help with repair of PSU

I will wait 2 days and try to find the problem with my teacher of electrotechnics

[UndeadLuke]

Re: LG 42LW4500-LB Need help with repair of PSU

The incoming mains of 230v ac is rectified to produce DC and then that DC voltage is increased by the circuit to approximately 380 - 400V DC.
There is no point in changing anything until you find that it is faulty!!!

Ah okey thanks I wil try check it with my teacher but also i found something this board has 2 circuit primary and secondary and i cant measure ohms on resistors on second circuit thats weird on first sector of board theres no problem with measure ohms on resistor