LC42SV50U Won't Turn On

[burner6999]

I am having trouble with a tv that I picked up to fix and give to a friend for his birthday. I have power to the supply. I also have power coming out. There is no lights or anything that come on when it is plugged in. I have tested all the voltages and have listed them in the picture. If I put 5v to the brown wire on the left, then the backlights come on. I have also purchased the service manual for the tv in hopes to fix it. Is there anything else that I can check? I cannot find a main board anywhere, but it looks like it is the culprit at this point. I have also tested the power at the switch that turns it on. the is a ground, and two other wires that have 3.3v then when the power is pushed one drops to 0v. I am not sure why the standby led does not light when it is plugged in either. I can't get pictures of the actual board right now, but nothing looks different then in the pictures. No bulging caps or anything burt.

[tech2014]

Re: LC42SV50U Won't Turn On

do you have standby voltage? If you have no power LED lit that usually means you are missing standby.

[burner6999]

Re: LC42SV50U Won't Turn On

I am not sure there is hardly any markings on the board. Where would I check for that?

[budm]

Re: LC42SV50U Won't Turn On

It looks to me you do have standby Voltage and you also have the PS-ON command signal to turn on the 12V and the 24V power supply but you are missing the BL-ON signal to turn on the backlights circuits.
Where is the picture of the backlghts Inverter board?

[burner6999]

Re: LC42SV50U Won't Turn On

I didn't include it because it was all working. If I put 5v to the brown wire the backlights come on.

[budm]

Re: LC42SV50U Won't Turn On

So the brown wire is the BL-ON pin, you will have to troubleshoot the main board next then to find out why the BL-ON is missing, and since you can force on the backlihts and if all other function of the main board is OK then you should see pictures on the screen if not then you have more than just BL-ON control signal problem.

[burner6999]

Re: LC42SV50U Won't Turn On

There is a reed LED at the bottom of the tv that is supposed to light up when the tv is plugged in but it doesn't either.

Any help on where to start with the main board.

[ljintexas]

Re: LC42SV50U Won't Turn On

PTS Electronics will repair and return your main board.

[dick_barton]

Re: LC42SV50U Won't Turn On

There's another thread on here which could be helpful

https://www.badcaps.net/forum/showthread.php?p=555792

[CapLeaker]

Re: LC42SV50U Won't Turn On

looks like you need a new main board if that file doesn't work.

[burner6999]

Re: LC42SV50U Won't Turn On

I saw that post already, but the usb doesn't seem to have any power. What would happen if I put >>>>>this board<<<<< in it? It looks identical in every way.

[CapLeaker]

Re: LC42SV50U Won't Turn On

It may work, but you have to set the panel up in the service menu, since the board is for a different screen size.

[burner6999]

Re: LC42SV50U Won't Turn On

Is this something you have done before?

[CapLeaker]

Re: LC42SV50U Won't Turn On

I've done it before. The hard part is you need to find a compatible main board, that supports the panel you have.

Lets say some support from 32" to 42" others from 46" to 50 something.

Either someone on here already knows what main board is compatible, or you have to do some research.