Plasma TV taking 15min to warm up?

Discussion in 'General Electronics Chat' started by JJS1234, May 31, 2011.

  1. JJS1234

    Thread Starter Member

    May 26, 2011
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    Hello everybody again. I was actually going to do what another member said to do- go to a e-waste junkyard and pick up a OK looking tv. But the manager people wouldn't even talk to me or let alone tell me when the vendor would come by to pick em up (thats privy information and we cant give that out). Well whatever.


    ANYWAY, turns out my grandfather has a 40-something inch plasma and he says it takes some 15 minutes to turn on/warm up. My guess (if plasma even has these) those illumination florescent lites that LCD TVs have.

    What do you think.

    At the moment this is just speculation until I pick it up later.
     
  2. tom66

    Senior Member

    May 9, 2009
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    Bad capacitors, I almost guarantee it.

    Take it apart, look for bulging caps. Good luck.
     
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  3. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Plasma's does not have CCFL's.. Like tom said, it could be capacitors
     
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  4. JJS1234

    Thread Starter Member

    May 26, 2011
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    Hey guys thanks for the reply.

    Im sorry, its a LCD. Specifically LG 37LC7D. My grandparents said it was plasma. THANK GOD it was not! They dont last as long.

    I will take a look at the caps in about 2 hours or so. Let you know by then.


    Other symtoms: Now that I have told you the model maybe the lights may come in handy too:

    So far it either:

    -Blinks 1 red and then 1 green OR

    -Blinks 5 green and 1 red

    either way takes actually (not 15 haha) about 1-2min to warm up.

    Will take a look at capacitors.
     
  5. tom66

    Senior Member

    May 9, 2009
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    The now recapped 42" LCD takes 5 seconds to warm up, so that is abnormal. I've seen similar symptoms before with LCDs. My Xerox monitor had a similar issue.
     
  6. JJS1234

    Thread Starter Member

    May 26, 2011
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    Really? I mean my other LG monitor (Flatron Wide 20") takes about 4 seconds. But I dont know if that counts since it shows the logo.



    Well in a little bit I am going to see what the capacitors look like.

    I depends really. If its not been on for the night it goes on in about a min or 2. If I turn it back on after 30min of no-use then it will turn on in about 10 sec.

    My guess is its the capacitors (what the posters mentioned above) and the fact the info on the internet also says that too.
     
  7. tom66

    Senior Member

    May 9, 2009
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    TV doesn't show logo. Green LED blinks three times then goes solid, backlight comes on, then the display comes on. To get to a TV picture, maybe 8 seconds. 5 seconds to backlight is fine; I was commenting that 1-2 minutes is abnormal.

    The fact that it is temperature dependent (the monitor will be warm if it has recently been switched on) tells me it's quite likely to be capacitors, as when near their limits, they are quite temperature sensitive. It's likely the power supply isn't stable until the caps have warmed up. On an older CRT, I might have said no to capacitors as they have much more analog circuitry which could be at fault.

    Either way, if it is still under warranty, I'd advise you take that route instead of repairing it yourself.
     
  8. JJS1234

    Thread Starter Member

    May 26, 2011
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    ALRIGHT: So I opened it up and what do I find?



    4 Bad or bulging capacitors. 1x 35v 1500uF 105C (m) and 3x 10v 2200uF 105C (m)


    ok so heres the question (couldnt find the 35v one at Frys):

    I talked with a guy at Fry's and he says that they dont have the exact ones for the 10v capacitors however he has 25v 2200uF 85C capacitors and tells me the voltage doesnt matter as much as the uF. So I buy 3 (.85$ ea.).

    Was he lying or can I use these?

    Im going to order the 35v one online since I cant find it there. They dont even have any 2200uF.


    Ill post pics soon. PS. The brand is NTE so I assume its better than the Chinese crap.



    Update: I Google-d "will capacitors work if the power is greater but the uF is the same" and got my answer.

    By the way does anyone have any experience with Newark.com, I was about to click "Pay" but their was no shipping cost- it wasn't even listed. Though the capacitors their are dirt cheap.
     
    Last edited: Jun 1, 2011
  9. tom66

    Senior Member

    May 9, 2009
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    Capacitance should ideally stay the same. Capacitance can increase for some power supplies - but here's the important part - not all of them will take it! Some will become unstable and not operate properly. Others will work better. But there is a reason the engineers chose that value. It would have come down to cost but also the amount of ripple that is acceptable on the power rails.

    Voltage should be the same or higher than what was originally installed. 25V caps will go bang after some time if they were on a 30V rail for example. The voltage rating is only the maximum tolerable voltage. However, higher voltage caps will be bigger (size wise) so consider clearances when putting them in the TV - will the case fit on?

    Honestly, the caps you buy from Fry's are going to be the lowest denominator; poor ripple current ratings, high ESR, and short life span; you'll just end up replacing them in another few months. I'd highly recommend when recapping a device, replace the capacitors with quality ones. I used Rubycon YXF. But Panasonic FM is good too, as is United Chemi Con KY series.

    You can buy them from Digikey, or in my case if you're in a rush, on eBay.
     
    Last edited: Jun 2, 2011
  10. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    8,754
    760
    When replacing them, try to check other's of the same value and voltage.

    It's good practice, for the fact that the caps might have come from the same batch. Check the value with cap meter for exact value or higher, if not, they are bad.

    If you don't have a meter, replace them all.
     
  11. tom66

    Senior Member

    May 9, 2009
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    Caps have a 20% tolerance out of the factory. If I see one 470u/25V bulging, I replace all instances in the power supply. Replacing all caps is a good idea, but a bit expensive.
     
  12. JJS1234

    Thread Starter Member

    May 26, 2011
    41
    0
    :p

    Already ahead of you. :D

     
    Last edited: Jun 2, 2011
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