Announcement

Collapse
No announcement yet.

Lg 32le4500

Collapse
X
Collapse
 
  • Page of 1
  • Filter
  • Time
  • Show
Clear All
new posts
Previous template Next
    #1

    Lg 32le4500

    Hi all,
    I use to repair TV's for my bread and butter but now do it as a hobby. I have the above tv from a friend for repairs. When the TV is turned on cold it comes on ok, I have set the unit to display the demo screen and it will happily continue to do this for hours and then the relay in the PSU will start turning on and off repeatedly. If I check the on/off voltage from main board to turn the PSU you, it is fluctuating. The back light also turns off. however if I partially remove the riser to the back light the backlight turns on, but the screen is blank. If it turn the set off and leave it for 45min its turns on again and is fine. I have replace ALL the electrolytic caps in the PSU, not sure where to look next ? could it be the main board ? are there any more electrolytics I could have missed or is it something else ?
    thanks in advance for any help
    kind regards
    Gavin
    Tags: None
    #2
    Re: Lg 32le4500

    Have you tried pressing on processor to see if if stabilizes?
    I assume no responsibility for any stupid suggestions I might post.

    Comment

      #3
      Re: Lg 32le4500

      Yeah, i also suspect a BGA issue.

      Comment

        #4
        Re: Lg 32le4500

        It is a bga issue. A proper re- balling will cure it.

        Comment

          #5
          Re: Lg 32le4500

          I'd just reflow it, a decent reflow will last years.

          Comment

            #6
            Re: Lg 32le4500

            Hi,
            thank you kindly for all your suggestions.
            Any nice tutorials you can recommend on bga reflow techniques ?

            Comment

              #7
              Re: Lg 32le4500

              I don't know of any actual reflow videos. Reflow implies that the solder is molten. All the "reflows" I've watched are just heating the board with flux to clean the oxide from the broken solder joints.
              I assume no responsibility for any stupid suggestions I might post.

              Comment

                #8
                Re: Lg 32le4500

                Reflowing is melting the solder. Some of the balls crack due to thermal expansion and contraction over time, mainly due to the lack of lead in the solder that allowed a little bit of flex.
                Reballing replaces the lead free balls with leaded ones that should provide a longer lifespan.

                Comment

                  #9
                  Re: Lg 32le4500

                  Originally posted by diif View Post
                  Reflowing is melting the solder. Some of the balls crack due to thermal expansion and contraction over time, mainly due to the lack of lead in the solder that allowed a little bit of flex.
                  Reballing replaces the lead free balls with leaded ones that should provide a longer lifespan.
                  Can you suggest a video of a real reflow?
                  I assume no responsibility for any stupid suggestions I might post.

                  Comment

                    #10
                    Re: Lg 32le4500

                    Originally posted by dskall View Post
                    Can you suggest a video of a real reflow?
                    I haven't watched one for years since I bought my rework machine.

                    They will look like the videos you are watching but without the stupid "cleaning oxidization from broken joints" comments and more "it's to reflow the cracked balls" comments. They have a profile that melts solder and they might nudge the chip to check the solder is liquidious and watch it spring back.

                    OP, There is a great thread on here with some decent home reflowing, use the search feature along with my username as I know I was in it, you should be able to find it.

                    Comment

                      #11
                      Re: Lg 32le4500

                      https://www.badcaps.net/forum/showth...home+reflowing

                      Comment

                        #12
                        Re: Lg 32le4500

                        Apologies, need to post to activate my posting of new threads.

                        Comment

                        Previous template Next
                        Working...
                        X