LG 47ls4500 no power

[Sniper82]

Got a 47ls4500 thats dead. I tested the fuses which are good but haven't had a chance to do much else. The power supply has a green LED on it which I am guessing if the power supply was good it would light up which its not. What should I check next?

For another power supply for this model its $80 on ebay. If I knew for sure it would fix the problem I'd probably get it but hate to spend that much on a power supply. I found one for another LG 47" alot cheaper but the rev and layout is just slightly different on the AC side. I was wondering if the specs on the connectors match is there a good chance it would work? The far right pic is of the cheaper power supply if someone could look at it. Thanks

[Sniper82]

Re: LG 47ls4500 no power

never mind on the different PSU I noticed the power connectors are different.

[Andrew F. Ali]

Re: LG 47ls4500 no power

Are you getting 5Vdc St-by voltage?

[Sniper82]

Re: LG 47ls4500 no power

not seeing pins that list a 5v stand by. I see a 24v power on. All the specs show a couple 12v, 3.5v and 24v.

[Sniper82]

Re: LG 47ls4500 no power

I just noticed this which doesn't look normal to me but maybe.

[MagicSmoke]

Re: LG 47ls4500 no power

Got a better pic of it on sj. Looks like this one uses 3.5v for stand by. Pins 5,6,17 and 18 on connector P201 should have 3.5v when plugged in but tv not on. Should be working because green led is on.

Pin 1 is designated by the black dot on board.

That's epoxy on the transformer, its normal.

The main board may not be sending the pwr-on signal back to psu to turn it on.

[Sniper82]

Re: LG 47ls4500 no power

I get no led(PSU or front of TV) power anywhere. However I get 3.5 when the mainboard is disconnected but once I connect it the 3.5v dies. So does this mean the mainboard could be bad? I wish I knew if the LED built into the PSU is suppose to function. Don't know why LG would put it there if it didn't.

[budm]

Re: LG 47ls4500 no power

So you do have 3.5VSTBY (generated by T501 transformer) but no indicator on the front panel at all.
It can be weak stby power supply or the main board is drawing too much current.
If it does not change state at all, then try disconnecting the cable between the main board and the T-CON board and see if it makes any different.
You can also load the 3.5V power supply with resistor to simulate load using 4.7 Ohms 5W resistor.

[Sniper82]

Re: LG 47ls4500 no power

I tried disconnecting everything on the main board but the cable to the power supply and it still dropped. I don't have any resistors to try. I just wish the power supplies LED was lit at least it would tell me to throw money toward the main board first. I may try to find a LED laying around just for the off chance it could be blown.

[Sniper82]

Re: LG 47ls4500 no power

well that didn't work. In your alls opinion what would you try and replace first?

[Sniper82]

Re: LG 47ls4500 no power

Well I bought a couple power supplies on ebay that was cheap but sold as is. They stated mainboard was replaced at the time of repair. So they may or may not work. Well I get them and both read 3.5v nothing connected but on both of them once the mainboard is connected the 3.5v is gone but every second it would register like .5v that comes and goes.

The onboard power supply LED light does not light at all on any of them so this tells me either the boards are bad or that LED only comes on when the TV is turned on or the led doesn't function at all. You all think its the mainboard?

[MagicSmoke]

Re: LG 47ls4500 no power

Yeah sounds like the mainboard is bad.

I have a Vizio 32" main that has a shorted dc/dc converter on it, same symptom PSU test good but would not turn on.

Of the 3 TV's I have repaired recently, on 2 of them when the psu failed it took the main with it or vice versa.

Edit... led's on the PSU usually only light when there is a fault on the PSU not on other boards.

[nomoresonys]

Re: LG 47ls4500 no power

check the first stickie post, by budm, its the first post in this category troubleshooting tvs, shows you how these tvs work, seems like you need to do the resistor to get the power on signal to the power supply, not sure bu you may be able to do a jumper wire to do it too, if no resistor handy, if the proper voltages are not coming from the power supply, the tv will not work right, careful when working with power supply, HIGH VOLTAGE, on primary side, could be deadly. actually you can get to it right from budm's post here post #8.

[Sniper82]

Re: LG 47ls4500 no power

thanks all for the help, turns out it was the mainboard. Got one cheap on ebay and it fixed it.

[Castlebravo]

Re: LG 47ls4500 no power

Hello Mr Sniper and all others
I have a LG EAY62512801 Power board with a bad (burned up) C603 cap. I was hoping that you might be able to look at your board and tell me what the value is of your cap. I don't know if your cap is C603 but looking at your board and mine....it looks like the circuits are very similar and making an educated assumption, I would suspect they are the same value. Unfortunately, The service manual doesn't have a Power Board schematic...that I've been able to find. The attached pdf is your board with a arrow and note. Thanks in advance for yours or anyone elses help in identifying this.

CB

[electrowiz1]

Re: LG 47ls4500 no power

Hello Mr Sniper and all others
I have a LG EAY62512801 Power board with a bad (burned up) C603 cap. I was hoping that you might be able to look at your board and tell me what the value is of your cap. I don't know if your cap is C603 but looking at your board and mine....it looks like the circuits are very similar and making an educated assumption, I would suspect they are the same value. Unfortunately, The service manual doesn't have a Power Board schematic...that I've been able to find. The attached pdf is your board with a arrow and note. Thanks in advance for yours or anyone elses help in identifying this.

CB

It's a 200PF 1KV

[Lil_n0e]

Re: LG 47ls4500 no power

Hi everyone I hate to post on an old thread but I'm having the same problem as electrowiz1 my cap at C603 is also burned out. Im gonna source a new cap using the value that was given of 200PF 1KV. I'm very green when it comes to circuit boards and working on them. I have standby power but my TV doesn't turn on. It went out while gaming, and the red led stanby light flickered and the screen shutdown like I turned it off. Then tried to turn it back on and the standby light would turn off but the screen wouldn't come back on. Everything on the rest of the boards looks fine and no signs of over heating and no other visibly burned components. My question is if I replace just the cap at C603 would that solve my issue? Do these caps typically just burn out or is it a sign of something bigger? Also when sourcing the 200PF 1KV cap is there anything in particular I should look for or are they all the same? Thank you very much.

[thoma]

Re: LG 47ls4500 no power

https://www.electronica-pt.com/esque...k-l102a-35116/

[nomoresonys]

Re: LG 47ls4500 no power

Hi everyone I hate to post on an old thread but I'm having the same problem as electrowiz1 my cap at C603 is also burned out. Im gonna source a new cap using the value that was given of 200PF 1KV. I'm very green when it comes to circuit boards and working on them. I have standby power but my TV doesn't turn on. It went out while gaming, and the red led stanby light flickered and the screen shutdown like I turned it off. Then tried to turn it back on and the standby light would turn off but the screen wouldn't come back on. Everything on the rest of the boards looks fine and no signs of over heating and no other visibly burned components. My question is if I replace just the cap at C603 would that solve my issue? Do these caps typically just burn out or is it a sign of something bigger? Also when sourcing the 200PF 1KV cap is there anything in particular I should look for or are they all the same? Thank you very much.

It's a capacitor they get old and slowly die, go ahead replace it, might be all that's wrong, as always heed the HIGH VOLTAGE WARNING CAN BE DEADLY, good luck.

[budm]

Re: LG 47ls4500 no power

Hi everyone I hate to post on an old thread but I'm having the same problem as electrowiz1 my cap at C603 is also burned out. Im gonna source a new cap using the value that was given of 200PF 1KV. I'm very green when it comes to circuit boards and working on them. I have standby power but my TV doesn't turn on. It went out while gaming, and the red led stanby light flickered and the screen shutdown like I turned it off. Then tried to turn it back on and the standby light would turn off but the screen wouldn't come back on. Everything on the rest of the boards looks fine and no signs of over heating and no other visibly burned components. My question is if I replace just the cap at C603 would that solve my issue? Do these caps typically just burn out or is it a sign of something bigger? Also when sourcing the 200PF 1KV cap is there anything in particular I should look for or are they all the same? Thank you very much.

Did you check the resistance of that cap? That cap is in the PFC Voltage booster circuit.
You need to at least report the DC Voltage on the connector of the power supply that goes to the main board when TV is off and when power switch is activated so we can at least what state the power supply is in.
You MUST put down the pin name and follow by the Voltage reading so we can easily see what they are.