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CAPACITOR QUESTION

Discussion in 'Beginner Electronics' started by Dennis Bush, Jul 31, 2003.

  1. Dennis Bush

    Dennis Bush Guest

    If my question seems stupid it is because I am new to this and trying my
    best to learn how to make repairs to some basic boards. OK Here goes:

    I had to replace two barrel type capacitors on a control board for a pinball
    machine. The capacitors were marked 470mfd35v and I replaced them with
    nichion 470uf35v. I read that you had to reform capacitors when replacing
    them. It that true for brand new capacitors or just used ones. Please email


    Thanks for your help
    Dennis
     
  2. miketinte

    miketinte Guest

    One is 470 microfarads will the other is 470 MILLIfarads... that's a
    huge difference....you might want to check that...I know that doesn't
    answer your original question
     
  3. DarkMatter

    DarkMatter Guest


    It would also be over ten times bigger physically. DOH!
     
  4. Dennis Bush

    Dennis Bush Guest

    Wow you folks really have me confused now. The original board and capacitor
    was made in early 1970 and are clearly marked nichion 470mfd35v. Now I went
    to several electronic suppliers and cannot find a 470mfd35v(millifarad) in
    a aluminum axial type capacitor which make me wonder now is it a microfarad
    marked mfd according to older standards or not. Man am I confused.

    Dennis
     
  5. DarkMatter

    DarkMatter Guest


    A 470uF at 35 volts is not that big a cap. Maybe 3/4" by 2" max.
    Low ESR models would be slightly larger.

    A 470 mF cap, on the other hand, is HUGE, not leaded at all
    (terminals), and likely not around anymore at all, except in surplus
    stores or military surplus.

    I can say with near total certainty that it is a 470 microfarads as
    you are not feeding a 20 amp circuit with the damned thing.
    %99.9999 certain.
     
  6. Lee

    Lee Guest

    No need for confusion, was the replacement caps 1000 times the
    physical size of the originals or not? There in lies your clue.
    mfd has always meant microfarad as has uf, don't let the doofus
    scare you so easy. If you want to talk millifarad you do it like
    this - 470,000,000uf. So it still comes down to microfarads.
     
  7. No manufacturer has EVER labelled a cap in millifarads.
    m is the antiquated designation for mico.

    ....I know !
     
  8. Overlord

    Overlord Guest

    I take it that the ufd is actually µfd then?
    Haven't been in this for a while now and I still look for mmfd on
    caps.
    (hope the news readers don't kill my old DOS keypad stuff....)

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