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Help Repair an LG LED TV No Power.

Discussion in 'Troubleshooting and Repair' started by Bradenro, Jun 4, 2013.

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  1. Bradenro

    Bradenro

    1
    0
    Jun 4, 2013
    Hi Guys, I've been looking around the web for info and videos on this matter and up to know I believe the problem is in the Power supply, but I'll break down the problem to see what you guys think.

    1. It's an LG 42LV3730, and the suspected not working board is the Power supply Part number. EAX63729001/7

    2. The symptoms: I plugged it in, and no power at all, no standby light, nothing.

    3. After opening it and looking around the Power Supply, I noticed the Main Fuse was blown, So I thought it would be an easy fix, So I replaced the fuse and connected the TV back on. (Yes, now I know this was a mistake, if the fuse is blown its probably because something else inside made it pop). When I connected it, I got a reaction from the standby light looked faded and slowly blinked, i pushed the ON button and the fuse popped again.

    4. Frustrated I've studied the board even more, and find no visible damage to any component, i have tested all the transistors, diodes, the fuses, the surge limiter, and cant find nothing wrong, since I don't have a Multimeter that can test Caps in circuit thats the only thing i haven't tested, but as they look fine I don't think they are the problem.

    5. Other tests, I have measured the outputs of the secondary with the TV plugged in, and with the cables connected and disconnected, and in either case i have gotten an output voltage, they are all flat 0V.


    I'll attach the pictures of the front and back of the board, and hope you guys have any Idea of what it could be, any info, or test I could do, let me know!

    Thanks in advance
    Any Help would be greatly appreciated
    Cheers
    Bradenro :confused:
     

    Attached Files:

  2. pistolpedro

    pistolpedro

    6
    0
    Jun 3, 2013
    looks like the board have 3 fuses. which one of them is popping?
    i am also on a hunt to find what is causing a fuse to pop.
    cheers
    pistolpedro
     
  3. pistolpedro

    pistolpedro

    6
    0
    Jun 3, 2013
  4. sheldonstv

    sheldonstv

    68
    0
    Jul 17, 2007
    check the bridge rectifier for shorts......if it is sc or the chopper sc it may be cheaper for you to replace the powersupply if its available -this repair may need a few sm parts replaced
     
  5. kkneo

    kkneo

    2
    0
    Jan 7, 2016
    Hi,
    I am facing almost similar problem on this LED tv. Power on light is on and after trying to switch on(via remote and touch sensor) the red light goes off but the screen does not turn on.
    Did you manage to rectify your tv?
    Appreciate if you could share what is the repair done?
    Any advise is welcome.
    Thanks.
    Regards.
     
  6. Sadlercomfort

    Sadlercomfort Ash

    424
    55
    Feb 9, 2013
    I would check the capacitors to see if they are bulging or leaking. This indicates the capacitor is bad.

    Look at the capacitors from the side so they look square, if you can see the metallic bit bulging its a bad capacitor. Capacitors can leak from the bottom or the top, (Usually the bottom) so check underneath the capacitor.
    [​IMG]


    kkneo, would you create a new detailed thread and include some photos if you have them? :rolleyes:
     
    Martaine2005 likes this.
  7. kkneo

    kkneo

    2
    0
    Jan 7, 2016
    Sorry for the late reply..
    New to this forum and there was no email alert to new posted reply. Realized It went to junk mail folder actually.

    The capacitor was alright on outlook wise. It was not bloated.

    Right now I am still not sure is it the power card issue?

    Regards.
     

    Attached Files:

  8. Sadlercomfort

    Sadlercomfort Ash

    424
    55
    Feb 9, 2013
    You may have to get the multi-meter out :oops:

    Its just a case of testing as you go, If you cant find a problem visually.

    The problem is what to test :rolleyes: perhaps someone with more experience can help.

    If your not getting any power at all, its clearly a big problem.. a protective device may have gone aswell.
     
  9. Dvspatel

    Dvspatel

    1
    0
    Jun 19, 2018
    Model no.42LV3730-TD
    My tv power stand by good 3.5v but power 24v pin and 12vX 3pin are not indicated by multimeter
    And tv stand by red light on but blue light not on
     
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