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main cap replacement on satellite receiver PS

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    main cap replacement on satellite receiver PS

    i need to replace main samYoung 68u 400v cap on PS in a pansat 3500 satellite receiver that overheated from being on top of a hot cable receiver, causing the 18x25 85C cap to leak a bit (see the left side in ps1.jpg). it still works, but i'm sure it's on its way to a potentially nasty failure. looking at mouser for 68u 400-450v compatible caps @ 105C gives me over a dozen choices.

    http://www.mouser.com/Passive-Compon...2&Ns=Pricing|0

    the board looks like it could fit up to a 20x40 cap. i hope someone will offer advice/info on what benefit a $4 cap has over the $2 version (i plan to get a couple of them so $4 is cheap enough as long as it doesnt get me useless overkill or the like). they are all panasonic, nichicon & united. the other caps on board are also samYoung, but show no leaks or bulges, so i'm not going to replace them now. thanks for your help
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    #2
    Re: main cap replacement on satellite receiver PS

    Originally posted by gb77 View Post
    i hope someone will offer advice/info on what benefit a $4 cap has over the $2 version (i plan to get a couple of them so $4 is cheap enough as long as it doesnt get me useless overkill or the like). they are all panasonic, nichicon & united.
    Generally, the large filter caps don't undergo a lot of stress due to where they are in the circuit.

    With digikey's presentation, I can see ripple values in the columns, but mouser doesn't list them. The ripple is about the only thing you have to worry about. It should be the same or more as the original.

    As for price, as long as it is one of the manufacturers above with the right ripple rating and it is a 105C cap, I would choose the lowest cost one.
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      #3
      Re: main cap replacement on satellite receiver PS

      Originally posted by gb77 View Post
      i need to replace main samYoung 68u 400v cap on PS in a pansat 3500 satellite receiver that overheated from being on top of a hot cable receiver, causing the 18x25 85C cap to leak a bit (see the left side in ps1.jpg).
      That's probably glue. Power supply manufacturers often glue down large caps so they don't move when being soldered to the board.

      Be careful though - that tan glue turns brown with heat over time and becomes conductive. While there may be no danger of this happening in this power supply, keep a look out if you see it across many components in other power supplies - if you do, remove as much of it as you can.

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        #4
        Re: main cap replacement on satellite receiver PS

        thanks for the glue info momaka, i already scraped some away from another contact, so i'll remove all i can - maybe i'll buy a couple caps next time i need other parts then.

        retiredcaps - found the samYoung datasheet - says 569mA @120Hz, so that narrows down the choices. digikey's ripple current rating isn't consistent about Hz, so have to go to the datasheets to find the 120Hz figure. from the nichicon sheet i see .5x1470=735 - am i doing that right? thanks again for helping
        samYoung datasheet
        https://cdn.badcaps-static.com/pdfs/...d928d89b06.pdf
        nichicon datasheet

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          #5
          Re: main cap replacement on satellite receiver PS

          Originally posted by gb77 View Post
          retiredcaps - found the samYoung datasheet - says 569mA @120Hz, so that narrows down the choices. digikey's ripple current rating isn't consistent about Hz, so have to go to the datasheets to find the 120Hz figure. from the nichicon sheet i see .5x1470=735 - am i doing that right?
          That looks correct to me.
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