LCD Monitor Repair

Discussion in 'The Projects Forum' started by vegas, Jan 8, 2011.

  1. vegas

    Thread Starter New Member

    Jan 8, 2011
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    Hi every one.
    Can anyone help with the following?
    My Pc LCD monitor has failed to power up and as i cannot afford to replace it i was possibly looking at repairing it myself.
    I have looked at a few posts regarding this on you tube and think i would be ok having a go at fixing it.
    I have removed the cover and found one capacitor with the top bulging like the ones in the video but none that are obviously leaking.
    There is however a few that i would like another opinion on so i can order all the parts needed in one go.
    I have attached two pictures of the other capacitors in question.
    JPG580 shows a large capacitor lying on its side, has it leaked or has it been glued down to the board.
    JPG580 shows around flat disc capacitor that looks like it has leaked (can these leak like the cylindrical ones)?
    JPG581 is along tube like capacitor that looks like it has leaked but has no obvious rupture to the surface, again can these leak?
    Please don’t be too harsh on me for my possible ignorance regarding the correct terminology names/description of things we all have to start somewhere LOL.
    Opinions and suggestions would be appreciated
    Thanks
    Dave
     
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Hey Welcome....
    I suppose you need to replace the caps.

    If you can solder & desolder, then take out the supply.
    Wait around 30 minutes after power down. Remove capacitor one by one and note down where that value is. Note the capacitance and voltage written on the cap and also note down the label written on PCB near that cap.

    Next buy the caps from a good source like digikey or mouser and just solder them back appropriately, that is positive to positive. Note the polarities

    Replace all the electrolytic caps. plus try to buy 105°C ones not 85°C ones.

    Note...disc capacitors do not bulge. Thus they are OK.

    Replacing all the electrolytes well help you prevent further problems related to caps
    The white stuff are glue...no worries.
     
  3. samitabassum

    New Member

    Jan 8, 2011
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    This is polar capacitor so when u replace it than check its polarity means postive and negative sidessss...
     
  4. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Did you not read my post?
     
  5. jason 77

    New Member

    Jul 27, 2009
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    I agree with what R!f@@ has said above about replacing all the electrolytic caps, but that might not be the reason why your monitor isn't working.


    That is a resistor not a capacitor by the way.
     
  6. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    I don't think that is the cap leaking. It looks like glue to me. If you look att he cap, it is radial. They wanted to lay it on the side for what ever reason, maybe clearance. If they just laid it on the side then there is nothing to keep it down. That is why whay glued it. The glue on the resitor could simply be a messy assembly person.
     
  7. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    What are the symptoms?

    Did it act odd prior to powering down? Do any lights come on? Did a shock occur? How old is it? Make/Model Number?

    Do you have a DMM?
     
  8. vegas

    Thread Starter New Member

    Jan 8, 2011
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    Hi
    Thanks to everyone who has replied so far.
    The monitor showed no issues when last used.
    When i switched on the power at the wall socket the little indicator on the front flashed 3 or 4 times.
    The colours were blue then yellow and then nothing.

    When working correctly:
    Blue indicates power on but not switched on.
    Yellow indicates on and in use.

    I have tried different leads and other sockets in the house but still no change.
    I have noticed that if you switch the power off at the socket straight after the lights have flashed and then back on again immediately the lights do not flash.
    If you wait 10 minutes or so the lights will flash again as before.
    Dave
     
  9. vegas

    Thread Starter New Member

    Jan 8, 2011
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    Sorry forgot to add

    it’s an LG Flatron Wide L194WT-SF 19” manufactured November 2006 Factory ID (MA) assembled in Poland.

    The monitor is used only by me at home so no unusual shock or misuse and only at weekends and occasionally in the week.
     
  10. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    you forgot to read the most important post.
     
  11. wayneh

    Expert

    Sep 9, 2010
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    I think jumping in to replace components without first getting a diagnosis will lead to a frustrating experience.

    How do you know the fluorescent backlight hasn't simply burned out? That's a very common failure mode, and an easy fix. How do you know there's anything wrong with your power supply? Without some measurements, you're fumbling in the dark.
     
  12. vegas

    Thread Starter New Member

    Jan 8, 2011
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    Well folk’s I have now replaced all the caps & the screen is clear and bright.
    I am currently browsing the internet using the repaired monitor.

    Thanks again to everyone who viewed & replied to my thread.
     
  13. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Nice..........
     
  14. SgtWookie

    Expert

    Jul 17, 2007
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    Looking at the photo on the right, it appears that the tall green capacitors are starting to fail, as the rightmost capacitor's top is bulging upwards significantly, and the same-type cap next to the blue resistor is starting to bulge. I would replace all of those capacitors with fresh ones of similar ratings (uF specification and voltage rating, 105ºC or better.)

    In the left photo, the horizontal black capacitor and the disk capacitor have adhesive on them to keep them in place.

    [eta]
    Wow, I guess I should've gone to page 2 before I posted. :rolleyes:
     
  15. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    Great job! So that was the caps that were leaking?

    Where did you get the caps so quickly?
     
  16. vegas

    Thread Starter New Member

    Jan 8, 2011
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    None of the caps were leaking only one cap was bulging on the top.
    I purchased the caps from a company called Maplin here in the Uk.
    I figured that with my limited knowledge the info form you guys, the web and the fact that the caps came to less than £10 i would give it a go as an equivalent replacement monitor would cost around £80 refurbished & £100+ new.
     
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