Choosing an in circuit ESR tester

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  • rb0746
    Member
    • Jan 2010
    • 42

    #1

    Choosing an in circuit ESR tester

    I am beginning to realize the the value of such a tool for trouble shooting .
    I was hoping to get some help in my selection/purchase.
    A Couple things to keep in mind are: 1) I live in Canada and 2) I am on a budget .
    Cheers
    Ron



    When I told my doctor I broke my leg in two places while carrying a big Monitor, he told me to stop going to those places.
  • bp1
    Member
    • Jul 2010
    • 46

    #2
    Re: Choosing an in circuit ESR tester

    I have just bought the esrmicro V4. Here are some links which you may find interesting on esr meters. They certainly helped me in my purchase choice.

    https://www.badcaps.net/forum/showth...257#post114257
    https://www.badcaps.net/forum/showthread.php?t=7394

    Hope the above helps

    kind Regards
    bp1

    Comment

    • tmwalsh
      Senior Member
      • Jan 2009
      • 119

      #3
      Re: Choosing an in circuit ESR tester

      I thought that all of the ESR meters worked with the capacitor under measurement out of circuit. Am I mistaken?
      tom

      Comment

      • Radio Fox
        Badcaps Veteran
        • Jan 2010
        • 281
        • UK

        #4
        Re: Choosing an in circuit ESR tester

        Originally posted by tmwalsh
        I thought that all of the ESR meters worked with the capacitor under measurement out of circuit. Am I mistaken?
        tom
        The only certain way of knowing if the ESR is OK, is to measure the capacitor out of circuit.

        Depending on the circuit layout, it is sometimes possible to measure the ESR while the capacitor is still in-circuit. If you measure a high ESR of a capacitor while in-circuit, then it is bad, but if it measures OK while in-circuit, it could be good or bad.

        Many circuits, especially PSU's have electrolytic capacitors in parallel. If your ESR meter shows both of these capacitors to be OK, it could be that one of them is still bad, but the good one in parallel is masking the high ESR.
        ________________________________________________

        Invisible airwaves crackle with life
        Bright antennae bristle with the energy
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        Comment

        • PlainBill
          Badcaps Legend
          • Feb 2009
          • 7034
          • USA

          #5
          Re: Choosing an in circuit ESR tester

          I would add to Radio Fox's explanation that interpreting the readings in terms of the circuit can help eliminate some of the guesswork. For example, if four capacitors are in parallel, the ESR spec of each capacitor is .06 ohms, and you get a reading of .03 ohms, the capacitors are bad (the expected reading would be .015).

          HOWEVER, capacitors are usually specified quite conservatively. When new, the capacitors probably each read .01 or .02; the circuit would work reasonably well if the total ESR was .5. Early this year I picked up a fairly new Philips LCD TV that was exhibiting the classic 'bad caps' symptoms. Most of the time it would start after a couple of tries.

          Opening it up, I found a number of bloated caps. Checking their ESR in circuit showed they read well over 1 ohm. Removing them from the circuit, each read much higher. The new capacitors were spec'd at something like .06 ohms, all read .01 or .02. Other similar capacitors in the TV gave readings well below .05. And when the caps were replaced, the TV worked perfectly.

          PlainBill
          For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

          Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

          Comment

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