Aluminum SMD caps vs thru hole caps (reliability)

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  • 13mh13
    Member
    • Jun 2022
    • 10
    • United States

    #1

    Aluminum SMD caps vs thru hole caps (reliability)

    The PCB motor for 1987 Technics SLP-120 CD player has slow spin-up issues. Similar to what another tech in the below video reported.


    https://i.postimg.cc/kGrR6BpZ/image.jpg

    Click image for larger version

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    I replaced the three bi-polar 47uF electros but that made no difference. The orig three bi-polar 47uF electros tested okay on my ESR M-tester.
    I have not tested/replaced those alum. SMD electro PCB caps.
    Are Al smd caps are more prone to failure (or degradation) than regular thru-hole electros?
    All the thru hole electros I removed / replaced on this CDP (and most vintage CDPs) are usually pretty good ESRwise (Made in Japan!!). But Vloss on these orig electro caps tend to be a little higher than a new electro caps.​

    That spindle in my SLP-120 spins very freely and has good inertia if I give it a twirl w/my fingers. I did oil the shaft on top and put small dab of Lithium grease on that plastic bearing on the bottom. Made no. diff.
    Note from the photo that there is a "set-screw" adj. for that bottom plastic (Teflon, Nylon??) bearing; it was factory Loctited and I did not touch it.



  • stj
    Great Sage 齊天大聖
    • Dec 2009
    • 30997
    • Albion

    #2
    smd electrolytics are shit.
    probably because they are undersized and the rubber bung is much thinner.
    i try to replace them with smd tantalums where it will fit.
    if you need to remove them and you dont have soldering tweezers or 2 irons and 3 hands, use the push&twitst method.

    Comment

    • lti
      Badcaps Legend
      • May 2011
      • 2547
      • United States

      #3
      Yes, SMD electrolytics are less reliable, and the early ones like yours were even worse. Caps that age are usually leaking by now.

      Comment

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