Using a multimeter continuity test on a cap

Discussion in 'General Electronics Chat' started by electronewb, Jun 6, 2012.

  1. electronewb

    Thread Starter Member

    Apr 24, 2012
    260
    3
    I'm trying to troubleshoot an audio breakout box basically a 2.5mm audio plug- capacitor inline to block DC-to XLR connectors I know that caps block DC how can I do a continuity test from the 2.5MM to the XLR connector? I think the capacitor block the continuity test on my meter!!!
     
  2. BSomer

    Member

    Dec 28, 2011
    433
    106
    Yes the capacitor will "block" the continuity test on your meter because your meter is sending out a DC voltage for test purposes. What kind of test equipment and related gear do you have available to use? Do you have an oscilloscope?
     
  3. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,771
    971
    Just test the portion up to and then the portion after the cap.
     
  4. vpoko

    Member

    Jan 5, 2012
    258
    47
    You could put an audio signal in through the 2.5mm plug, connect your meter in series between the XLR plug and ground (which should be common to the audio source's ground), then check for current.
     
  5. electronewb

    Thread Starter Member

    Apr 24, 2012
    260
    3
    Yes I have a scope So I guess I could send an audio signal like vpoko mentioned and look at the signal. I figured out it's the connector but I'd like to know what's the best way to troubleshoot a capacitor when it's in a circuit and also I don't always have access to a scope!! Can I charge a capacitor with a 9V battery? Or I can only charge it with AC?
     
  6. vpoko

    Member

    Jan 5, 2012
    258
    47
    Why do you want to charge it? If it's broken, isn't the only solution to replace it?
     
  7. electronewb

    Thread Starter Member

    Apr 24, 2012
    260
    3
    It's not broken I want to be able to test a capacitor in a circuit
     
  8. BSomer

    Member

    Dec 28, 2011
    433
    106
    Google "ESR meter". There are some home brew circuits out there that can test a capacitor in circuit. ESR is Equivalent Series Resistance, the meter basically inputs a small signal into the capacitor and determines its resistance. There are also some videos on youtube showing how it works.
     
  9. electronewb

    Thread Starter Member

    Apr 24, 2012
    260
    3
    That's where I am in my research... ESR meters on ebay!!! I have the Fluke 87 DVM which test capacitors so far all I've been able to test are non electrolytic caps When I test an electrolytic cap I get O.L (overload)
     
  10. electronewb

    Thread Starter Member

    Apr 24, 2012
    260
    3
    OK I think I found the problem!!! There's 2 caps in that circuit One to block DC to a microphone and another cap to block DC on the audio output. I tested it it with 1K sine wave the cap for the mic passes the wave but the cap for the audio output has nothing. It's a 10V 10u What other values could I use to replace that cap just in case they don't have what I'm looking for at the electronic store?
     
Loading...