Help me repair a motherboard with short circuit

Discussion in 'General Electronics Chat' started by rui771, Jul 12, 2015.

  1. rui771

    Thread Starter New Member

    Jul 12, 2015
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    Hi there i have this computer packard bell easy note ts 11 hr 244 pt with this motherboard:
    sjv50_hr /p5weo La-6901p rev 1.0

    I was using my laptop normally and suddenly it goes off (it happens sometimes )..after that there is a only light in the laptop with adapter and battery.
    When i plug the ac adapter in the Laptop and try to turn on the computer, it shutdowns after 3 secs(i can see the fan spinning and the leds ).

    i have tested other ac adatper ,removed rams, removed the baterry and changed the jack and the problem persists.The temperatures are 40-50º arround iddle and 77º playing games(sometimes i can turn on the pc )
    I am trying to find a short on my motherboard,I dont know which component causes a short, since i dont have skills ,so far i tested the dc adapter with a multimeter and it says 19.45 v .

    i can provide a diagram of the motherboard and images, need some help .
     
  2. ISB123

    Well-Known Member

    May 21, 2014
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    How can you be sure that there is a short?
     
  3. rui771

    Thread Starter New Member

    Jul 12, 2015
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    because i went to a store and they told me that , and when i try to turn on the pc i can hear a noise(not fans spinning) and when i press the button i see the led of charger flashing then after 1-3 secs it shutdowns till i remove ac adapter .

    [​IMG]
     
    Last edited: Jul 12, 2015
  4. ISB123

    Well-Known Member

    May 21, 2014
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    Take a HD picture of your motherboard from top and bottom side.
    What kind of noise do you hear?Maybe a whine sound?
     
  5. paulktreg

    Distinguished Member

    Jun 2, 2008
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    A stock reply from a store will be "it's shorted", it doesn't really tell you much and if they offer a repair service they'll want to sell you a new motherboard or laptop.

    You'll find any computer motherboard, laptop or PC, very difficult to fault find and repair next to impossible unless it's the processor or RAM IMO.
     
    absf likes this.
  6. rui771

    Thread Starter New Member

    Jul 12, 2015
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    the noise takes 1- 3 secs it sounds like a taser ""
    here it is from my huawei p8.

    http://imgur.com/5TiNQFG


    http://imgur.com/bcr5a0c

    it you take a look on those mofets close to battery , they are a little bit yellow , does it means anything?
    i have also attached the diagram of this mobo.
     
  7. rui771

    Thread Starter New Member

    Jul 12, 2015
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    any1?
     
  8. Brevor

    Active Member

    Apr 9, 2011
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    Nope, I think it's time to start looking for a new laptop.
     
  9. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    You might need to reflow the chipset
     
  10. rui771

    Thread Starter New Member

    Jul 12, 2015
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    i am going to do it as last resource, but like i said before when i try to turn on the PC sometimes(after 50 attempts...) there is image and i can go to the browser or play a game for a while and suddenly it shutdowns and also when i try to turn on the pc the charger led flashs a little bit on those 3 seconds.Isnt it a sign of a short circuit (i tested other charger and does the same)?
     
    Last edited: Jul 13, 2015
  11. ISB123

    Well-Known Member

    May 21, 2014
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    Pretty sure if you had a short circuit it would refuse to turn on and charger would refuse to charge.
     
  12. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    A short circuit is not the culprit.
    Playing games might cause it overheat and cause dry joints
     
    PackratKing likes this.
  13. rui771

    Thread Starter New Member

    Jul 12, 2015
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    thats what iam trying to say, sometimes that happens, when i try to turn on pc the led of charger turns off and computer too and sometimes i can run the PC normaly (or it shutdowns in the middle of windows loading or bios...).

    Like i said before i always controll temperetures while gamming after long period of time, and it doesnt pass 77º.
     
  14. ISB123

    Well-Known Member

    May 21, 2014
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    Sounds like broken charger/battery.Did you try clearing CMOS?
     
  15. rui771

    Thread Starter New Member

    Jul 12, 2015
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    yes that was one of the 1º things i did , i have repaired the charger already 1 time, but i tested the pc with a new 1 and happened the same so i dont think it is the charger, and like i said before it happens with or without battery in( it is decteted by the windows and the multimeter says 12v when i plug in).
     
  16. Lestraveled

    Well-Known Member

    May 19, 2014
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    Can you operate the computer with the cases off? The idea would be to get a few cans of freeze spray and freeze sections of the board. If you are lucky, you will find a section that when you keep it cold, the computer will run. Then work down to the component. Get the idea??
     
  17. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Dry joints once caused remains. And results in intermittent fault. It's not a short.
    Only way is reflow (temporary) or reball. Both job you cannot do I believe.
     
  18. rui771

    Thread Starter New Member

    Jul 12, 2015
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    i have a friend that can do it for me.
     
  19. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Then do it
     
  20. rui771

    Thread Starter New Member

    Jul 12, 2015
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    So my friend did a reflow and didnt work, same issue... because he doesnt have equipmento to do a reball(and for that i have to search for a store and cost around 90€).

    any other thoughts?
     
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