Repairing Your Own Digital Capacitance Meter

By on August 7, 2010

capacitor tester

Have you encounter before a blown digital capacitance meter caused by undischarged voltage from the big filter capacitor? Sometimes one may have forgotten to discharge the big capacitor and directly place the test leads on the cap. You will hear a sound “Pop” and then the display will go off. The sound was from the fuse (usually 0.25 amp) and usually after replacement of the fuse, the meter will still not work and it may have a running display. I have to admit that i accidentally blown about few digital capacitance meter during the early days of using it. As time progress, you will automatically  discharge the cap before using it. I had few meters also that had accidentally blown by new staff.

My point here is that one must take care of this meter and usually once it blow, although you can replace the fuse and some of the components in it, the meter will still not work. This is because the surge from the big capacitor was too great that it penetrate to the CPU IC in the meter.  Since i have few similar meters with me thus it was easy for comparison. Have you come across such situation before? Are you  able to repair the meter?



  1. Waleed

    August 7, 2010 at 2:14 pm

    In fact, I had one in the shop today and the display is on but when checking any capacitors, it does not register anything. the fuse is ok and the display is ok but not reading anything..any hints?

  2. admin

    August 7, 2010 at 10:19 pm

    Hi Waleed,
    Try trace from the red probe lead and see if there is any component shorted or not. In my case it was usually small transistor problem.


  3. Rich Beinlich

    August 8, 2010 at 1:17 am

    Ive blown my Capacitor Wizard ESR meter once. Usually a few low ohm resistors open. Luckily in the manual they tell you what to check and part numbers if you accidentlly test a charged cap. You learn from your mistakes!

  4. Waleed Rishmawi

    August 8, 2010 at 3:28 am

    the capacitor meter that I am working on is CM9601A. You were right. I traced the red probe and right after the main fuse, there was a resister fuse 10 ohm that is open. changed that and it worked nicely. thanks for the tip. God bless you

  5. admin

    August 8, 2010 at 4:43 am

    Hi Rich,

    Thanks for the sharing!


  6. admin

    August 8, 2010 at 4:45 am

    Hi Waleed,
    Good to know that but mine was TES1500 model and usually the CPU will have problem when hit by the big surge from the big filter capacitor. Rich was right that we learn from our mistakes.


  7. rey

    January 27, 2011 at 1:28 am

    hi justine i have a multimeter w/ capacitance meter.its not working anymore because of defective lcd driver,how can i replace it. built in pcb, i wish to make another driver,do you know any ic that will be suitable for the lcd. my meter is mastech m9704

  8. admin

    January 27, 2011 at 9:03 am

    HI Rey,

    Sorry i have no info on that. Usually parts for test equipment are quite hard to locate from the market.


  9. Mircea

    November 17, 2013 at 3:25 pm

    You check capacitors with ESR meter that I put on the input protection diodes. Have a nice day Jestine!

    • Amendar

      December 22, 2013 at 12:22 pm

      Would you let us know how did you that?

      • Jestine Yong

        December 22, 2013 at 11:49 pm

        Hi Amender,

        If the meter is spoilt one has to open it up and check for bad components. If the CPU ic have problem then there is no way to repair it.


  10. Matias

    January 28, 2016 at 3:59 am

    Waleed, i'd like to kiss you right now, same 10ohm resistor gave up on me, fixed it in minutes! Cheers mate!!!


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