How many caps do I replace and voltage?

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  • AlanSmithee
    New Member
    • Sep 2012
    • 1
    • Canada
    #1

    How many caps do I replace and voltage?

    I'm fixing a PSU in an LG Plasma tv, the owner paid $5k for it, and doesn't want to part with it....from the described symptoms it sounded like bad caps to me, and sure enough it was. I also found a lot of references online to the same issue. My first experience with bad caps was an Apple Airport Graphite, with Lelon caps...about when I started googling symptoms WHENEVER something craps out - there's always a duplicate experience out there...

    I picked up some parts on spec, having not seen the actual supply but I had some online references for values. The originals are 3300uf 10v, I got 25v ones. Not only were they expensive, they're rather too large (although I MIGHT be able to make them fit, if I stand them off the board a bit, the lead spacing is the same.)

    I can't quite read the name of manufacturer (hell getting old) but it strikes me, since every bad cap is identical, is it the manufacturer, or the voltage rating or both? They're all marked as 105degree, but if they run at close to the mfr rated voltage, is that an issue in itself?

    I wonder if I should use the 25v ones, or see if there's a 16v equivalent? I don't really want to order online and get stuff shipped if I can help it, I want to get this done asap. (I do pay a large $$premium, buying in a small town.)

    I realise there could be a difference in performance, using higher voltage (more ripple?) but typically, most mfrs overspec their components, right?

    My last question is, if the other caps on the board appear ok, should I leave them? I'm inclined to, especially the expensive ones...although there are a couple that look like they're the same brand. I guess it would be prudent to replace those ones.
    Tags: None
    • mariushm
      Badcaps Legend
      • May 2011
      • 3799
      #2
      Re: How many caps do I replace and voltage?

      The capacitors are available in standard voltages - for electrolytic capacitors, the standard voltages are 6.3v, 10v, 16v, 25v, 35v, 50v and up.

      The most probable cause for those capacitors going bad is excessive heat and poor quality of the capacitors - some brands or some series of capacitors made by certain manufacturers are just not able to cope with the heat in tvs.

      It's unlikely the capacitors have issues because voltage is close to the capacitors' voltage rating. You can use those 25v rated capacitors and chances are they'll last a long time if they're made by a good brand and match or exceed the technical specs of the old capacitors, simply because as their size is larger, so is their ability to tolerate heat.

      So... voltage is not really a factor, but rather the quality, who makes the capacitors and what technical specs the capacitors have.

      Those 3300uF 10v have something written on them, the manufacturer or the very least a 2-3 letter code which is the series. You can then check the datasheet and see what would be adequate for replacing those.
      If you can't figure out those old capacitors, post some pictures of them here as clear as possible and we'll show you how to get proper replacements.

      Chances are this website has suitable capacitors for you on its online store, if not there's online stores with good reputation we can suggest.

        Comment

        • retiredcaps
          Badcaps Legend
          • Apr 2010
          • 9271
          #3
          Re: How many caps do I replace and voltage?

          Here is my standard answer for replacing caps below (regulars may skip)

          https://www.badcaps.net/forum/showpo...84&postcount=3

          Note: If the caps are on the power supply, low ESR caps are required.

          If the guy paid $5K originally, he shouldn't mind spending around $15 to $20 for quality caps from a reputable dealer.

          edit: Romania has faster ISP speeds than Canada!
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          We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

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