PCB help for a LG tv

Thread Starter

Donaldk20

Joined Dec 19, 2020
7
Hey there , my 1 year old tv recently stopped working , I’m not familiar with these stuff but I’m trying to figure out which is defective in order to replace it. The tv has no standby light showing and does not turn on, the power supply board keeps making a ticking sound, I have checked the voltages at each pin and get fluctuating readings any help would be appreciated
 

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drc_567

Joined Dec 29, 2008
1,110
... The wires near the J22, C610, area in picture #2 seem to be discolored, possibly carbonized due to excess heat, and there may be a small bubble on one of the blue disk capacitors. Can you verify this?
 

Thread Starter

Donaldk20

Joined Dec 19, 2020
7
... The wires near the J22, C610, area in picture #2 seem to be discolored, possibly carbonized due to excess heat, and there may be a small bubble on one of the blue disk capacitors. Can you verify this?
Are you talking about this ? Appears the sound is coming from that area when I put my phone close to it, now the question is does that little component usually break or did something cause it to fail. In that case I’ll have to do further more troubleshooting
 

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drc_567

Joined Dec 29, 2008
1,110
That is it. Do the blackened wires indicate carbonization? It seems that they should be bright and shiny. However, the primary or first part that failed is going to take some investigation to track down. Usually, a circuit diagram makes things a lot simpler.
 
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Thread Starter

Donaldk20

Joined Dec 19, 2020
7
... The wires near the J22, C610, area in picture #2 seem to be discolored, possibly carbonized due to excess heat, and there may be a small bubble on one of the blue disk capacitors. Can you verify this?
That is it. Do the blackened wires indicate carbonizatuon? It seems that they should be bright and shiny. However, the primary or first part that failed is going to take some investigation to track down. Usually, a circuit diagram makes things a lot simpler.
yes , that’s a good idea, i will go ahead and start by replacing this,if the problems persists I will just buy a new power supply as this is my only tv and I am left tvless haha. I will keep you updated thank you
 

MrChips

Joined Oct 2, 2009
23,535
I am going to guess that the ticking sound is the power supply is trying to start up and can’t make it. It could be that the power supply is fine but something else is loading it down.
 

Thread Starter

Donaldk20

Joined Dec 19, 2020
7
... Check with the manufacturer about a replacement board. It should have lasted more than one year.
I tried but appeantly I had to set up the warranty with them, I thought it was given automatically but you have to actually call them and activate it ,now it’s too late. Funny how a 1 year old tv is already broken when my old Panasonic tv is still working perfect after 10 years
 

drc_567

Joined Dec 29, 2008
1,110
... Replacing the faulty capacitor, only, will not be advisable. There is some unidentified part whose failure initiated a chain of events, resulting in the final outcome.
 

Thread Starter

Donaldk20

Joined Dec 19, 2020
7
I am going to guess that the ticking sound is the power supply is trying to start up and can’t make it. It could be that the power supply is fine but something else is loading it down.
Yes I assumed that too since on the voltmeter I saw the voltage trying to rise but it kept going back down like something was causing it to drop (4.3 to 3.7 over and over again). I removed the wire from the power supply to the logic board and the ticking stops now the readings are a steady voltage of 7.9. What I’m stuck on now: is the power supply bad or the logic board, I can’t quite tell since the standby voltage is not given. I see a 12.3 v on the board but I assume it’s the voltage it is when ruining so I’m not certain 7.9 volts is good or bad
 

Thread Starter

Donaldk20

Joined Dec 19, 2020
7
... Replacing the faulty capacitor, only, will not be advisable. There is some unidentified part whose failure initiated a chain of events, resulting in the final outcome.
Yes that’s what I think too, which is why I might just end up replacing the power supply completely. It’s 40 bucks and it has 6 months warranty , If it fails again then I’ll have to find a circuit diagram somehow and work from there
 

LesJones

Joined Jan 8, 2017
3,181
Are you sure that that what are being referred to as "black wires" near C610 and J22 are wires. I think it is a slot milled in the board for extra insulation and that the discoloration and the bubble on the capacitor is insulating varnish.
Also I think the ticking is the power supply shutting down because it is is sensing an overload on one of it's outputs. If this is so the fault could be on one of the other boards in the TV.

Les.
 

drc_567

Joined Dec 29, 2008
1,110
Are you sure that that what are being referred to as "black wires" near C610 and J22 are wires. I think it is a slot milled in the board for extra insulation and that the discoloration and the bubble on the capacitor is insulating varnish.
Also I think the ticking is the power supply shutting down because it is is sensing an overload on one of it's outputs. If this is so the fault could be on one of the other boards in the TV.

Les.
That is definitely a possibility ... slots, not wires. There is a clear fluidic substance around the capacitor with the bulge. Maybe it is a varnish or coating of some sort.
 
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