DFI nF4 recap with all polymers?

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  • cmr-informatik
    New Member
    • Jun 2019
    • 5
    • USA

    #1

    DFI nF4 recap with all polymers?

    Hi everyone,

    I have some DFI nF4 boards coming in to try and relieve some nostalgic times. A few of the boards have bulging caps and I'd like to just recap the entire boards to make a fun project of several weekends.
    I am not entirely new to this replacing caps thing, having swapped out some bad caps on original Xbox motherboards while completing my EE undergrad.

    I am curious if there are any electrical issues (yes my undergrad is EE but I mostly work in CPU logic design and OS/firmware now so... it's been a while hah) with replacing all caps on DFI nF4 motherboards with equivalent polymers (cost isn't really a concern, but availability might be I suppose)?

    From what I recall, I should match capacitance and voltage spec, along with similar ESR (or lower). It looks like the circuits around the CPU are already polymers on these motherboards so I won't be replacing those if I don't have to.

    Am I missing anything? Is this really dumb ?
  • ChaosLegionnaire
    HC Overclocker
    • Jul 2012
    • 3264
    • Singapore

    #2
    Re: DFI nF4 recap with all polymers?

    i have seen plenty of those with bulging caps on ebay. these dfi nf4 boards typically come with a boardful chemicon kzg caps which are known to be problematic and they are used for general filtering of the minor rails. this fits in with what we know of the failure mode of the kzg series in that the lower voltage parts typically the 6.3v caps fail the quickest.

    however, dfi was wise to use polymers in the cpu vrm and the dfi nf4 boards typically have chemicon psc blue polymer caps which are great and long lasting and dont cause issues.

    that being said, u dont need polymers in the places the electrolytic kzg caps bulged because they are low stress minor rail filtering areas where u can take liberties with the esr and ripple rating spec. there are over 20 of them per board and replacing them all with polymers will break the bank easily. just use 10k hour electrolytic caps series like panny fr, rubycon zlh or chemicon kzm. they will work fine without issue.

    Comment

    • stj
      Great Sage 齊天大聖
      • Dec 2009
      • 31012
      • Albion

      #3
      Re: DFI nF4 recap with all polymers?

      make sure the pitch between the leads is correct when you order the polys,
      unlike electrolytics, polys can come with different pitch options for the same cap diameter.

      Comment

      • cmr-informatik
        New Member
        • Jun 2019
        • 5
        • USA

        #4
        Re: DFI nF4 recap with all polymers?

        Thanks guys!
        I will most likely be following up with a post in the Motherboard section once all the boards and parts are here.

        Comment

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