Lenovo E520 Backlight Problem..

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  • wainy54
    New Member
    • Jun 2013
    • 4
    • United Kingdom
    #1

    Lenovo E520 Backlight Problem..

    Hi All,

    I'm attempting to repair my Lenovo E520 laptop. It suffered a small fall, which shattered the LCD. I've managed to replace this, however the backlight isn't working. Annoyingly its not just a bad screen, seems like a mainboard issue.

    After a bit of digging, looks like there are two fuses on the board that may have failed. I'm looking to swap or short these out. Found some info on this polish forum.


    http://www.elvikom.pl/forum/viewtopi...839&view=print

    I found markings for the fuses in question (F4901 & F4903), however I'm not certain which SMD are the fuses. See this pic (sorry cant seem to embed it):

    https://www.dropbox.com/s/ijl7h52l60...2-15-14-41.png

    Could anyone offer any help identifying the fuses?

    Thanks
    Wainy
    Last edited by wainy54; 06-22-2013, 01:00 PM.
    Tags: None
    • trebo
      Badcaps Veteran
      • Feb 2010
      • 514
      • Wales, UK
      #2
      Re: Lenovo E520 Backlight Problem..

      Originally posted by wainy54
      Hi All,

      I'm attempting to repair my Lenovo E520 laptop. It suffered a small fall, which shattered the LCD. I've managed to replace this, however the backlight isn't working. Annoyingly its not just a bad screen, seems like a mainboard issue.

      After a bit of digging, looks like there are two fuses on the board that may have failed. I'm looking to swap or short these out. Found some info on this polish forum.


      http://www.elvikom.pl/forum/viewtopi...839&view=print

      I found markings for the fuses in question (F4901 & F4903), however I'm not certain which SMD are the fuses. See this pic (sorry cant seem to embed it):

      https://www.dropbox.com/s/ijl7h52l60...2-15-14-41.png

      Could anyone offer any help identifying the fuses?

      Thanks
      Wainy
      fuse above "f4" of f4903
      and other fuse above "90" of f4901, in your picture

        Comment

        • wainy54
          New Member
          • Jun 2013
          • 4
          • United Kingdom
          #3
          Re: Lenovo E520 Backlight Problem..

          Thanks. I've just tested F4903 (above "F4") and that seems intact with continuity. F4901 appears to be the problem, I will treat this to a blob of solder sometime tomorrow. Wish I could replace it, but I simply don't have the equipment and its just so tiny....

          I will give it a go and report back.

          Thanks again.

            Comment

            • wainy54
              New Member
              • Jun 2013
              • 4
              • United Kingdom
              #4
              Re: Lenovo E520 Backlight Problem..

              Thanks again trebo, I removed the blown fuse and soldered in a small length of jumper wire. It was a bit of a battle, due to the size of the fuse and my relatively huge soldering iron tip (maybe time to spend some £££) but managed it in the end.

              Now I'm glad to report the laptop is working once again.

              Wainy

                Comment

                • usman1972
                  New Member
                  • Mar 2015
                  • 1
                  • united kingdom
                  #5
                  Re: Lenovo E520 Backlight Problem..

                  Originally posted by wainy54
                  Thanks again trebo, I removed the blown fuse and soldered in a small length of jumper wire. It was a bit of a battle, due to the size of the fuse and my relatively huge soldering iron tip (maybe time to spend some £££) but managed it in the end.

                  Now I'm glad to report the laptop is working once again.

                  Wainy
                  Many Thanks
                  it work for me too it was fuse above F4901 the middle one just jumper with wire don't have to remove just jumper it.

                    Comment

                    • ncdave
                      Member
                      • Oct 2003
                      • 33
                      • USA
                      #6
                      Re: Lenovo E520 Backlight Problem..

                      wainy54, trebo & usman1972, you saved me! I was at my wit's end.

                      The culprit on mine was F4901, too. Unlike yours, mine was marked with a tiny "3" which could be read with a jeweler's lupe. (The other two fuses, F4902 & F4903, were marked F and G, and were not as tiny.)

                      I think that's the tiniest thing I've ever successfully soldered. Wow, that was hard.

                      This is my magnifying glass kludge (my biggest magnifying glass lashed to a gooseneck lamp to hold it in place):
                      http://www.geeksalive.com/magnifying...E520_25pct.jpg

                      Here's a closeup of the F4901 (culprit) fuse location:
                      http://www.geeksalive.com/Lenovo_E52...it_closeup.png

                      Here's the full-sized photo of the F4901 fuse location:
                      http://www.geeksalive.com/Lenovo_E52...ad_culprit.jpg

                      Does anyone know where to get those clamp-on-your-glasses binocular magnifiers which the dentists use? I need a pair!

                      I also need to get a soldering iron with a shorter tip-to-grip length. It was really difficult to keep the tip of my trusty 50yo Ungar steady enough to solder that tiny fuse. Does anyone have a recommendation?

                      Has anyone tried the Pro'sKit SI-B161 battery-operated 9W soldering pencil? In the photos, it looks like it has a pretty short tip-to-grip length, unless the black part near the front gets too hot to hold.
                      Last edited by ncdave; 03-31-2015, 01:59 AM.

                        Comment

                        • tibimakai
                          Badcaps Legend
                          • Jan 2012
                          • 3680
                          • USA
                          #7
                          Re: Lenovo E520 Backlight Problem..

                          ncdave, what was your problem with the laptop?

                            Comment

                            • dlshad96
                              Member
                              • Apr 2016
                              • 39
                              • Us
                              #8
                              Re: Lenovo E520 Backlight Problem..

                              Originally posted by usman1972
                              Many Thanks
                              it work for me too it was fuse above F4901 the middle one just jumper with wire don't have to remove just jumper it.
                              Hello Guys


                              i have same laptop Thinkpad E520 yes its the fuse problem the lite back but no data the screen now is white the led working but no data . before was black screen working with only external screen.

                              working with external monitor fine , i change the internal led screen its same no data change the cable same problem

                              testing the screen with another laptop the screen working well.

                              could you please helping me whats the correct part i have to replace it.

                              Thank you in advance.
                              Last edited by dlshad96; 04-19-2017, 02:09 AM.

                                Comment

                                • String2016
                                  Badcaps Legend
                                  • Nov 2015
                                  • 2238
                                  • philippines
                                  #9
                                  Re: Lenovo E520 Backlight Problem..

                                  Originally posted by usman1972
                                  Many Thanks
                                  it work for me too it was fuse above F4901 the middle one just jumper with wire don't have to remove just jumper it.



                                  Where to make a jumper wire can you show a photo please

                                    Comment

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