Don't Miss

Repairing Your Own Digital Capacitance Meter

By Jestine Yong on August 7, 2010

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?

Likes

(7)Dislikes

(0)

18 Comments

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?

Likes(0)Dislikes(0)

Reply
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.

Jestine

Likes(0)Dislikes(0)

Reply
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!

Likes(0)Dislikes(0)

Reply
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

Likes(3)Dislikes(0)

Reply
admin

August 8, 2010 at 4:43 am

Hi Rich,

Thanks for the sharing!

Jestine

Likes(0)Dislikes(0)

Reply
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.

Jestine

Likes(0)Dislikes(0)

Reply
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

Likes(0)Dislikes(1)

Reply
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.

Jestine

Likes(0)Dislikes(0)

Reply
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!

Likes(1)Dislikes(0)

Reply
- Amendar
  
  December 22, 2013 at 12:22 pm
  
  Dear,
  Would you let us know how did you that?
  Thanks
  
  Likes(0)Dislikes(0)
  
  Reply
  - 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.
    
    Jestine
    
    Likes(0)Dislikes(0)
    
    Reply
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!!!

Likes(0)Dislikes(0)

Reply
Earle Brown

February 20, 2020 at 3:08 am

Ive got a b&k 810A capacitance meter, the display has gone blank, have cleaned the rubber coupling and the circuit traces no luck. How can i tell if the cpu or the lcd displai is blown.
Thanks

Likes(0)Dislikes(0)

Reply
- Jestine Yong
  
  February 24, 2020 at 9:59 am
  
  Hi Earle,
  
  It's hard to tell because there was not much info about meter circuitry and schematic-unless you have a similar one for comparison. This means that, if the CPU is receiving the right voltage/signal and not overheated and if the memory IC was not corrupted chances is high the CPU is good. Same goes to LCD display, if it received the right voltages/signals and did not lighted up, it could mean the lcd display could have problem.
  
  Jestine
  
  Likes(0)Dislikes(0)
  
  Reply
  - Earle Brown
    
    February 25, 2020 at 11:27 pm
    
    Hi Jestine,
    Is there any way to test the LCD display( with the zebra connector) to know if it is working.
    Thanks
    
    Likes(0)Dislikes(0)
    
    Reply
    - Jestine Yong
      
      February 27, 2020 at 2:57 pm
      
      Hi Earle,
      
      It is difficult to test without having the schematic and the same parts. Internet has very limited information about repairing meter LCD display.
      
      Jestine
      
      Likes(0)Dislikes(0)
      
      Reply
Vigneswaran g

June 4, 2020 at 11:40 pm

I have v8222h multimeter I measured charged capacitor. Now it's not showing capacitance value anymore can u tell me tip to repair it..

Likes(0)Dislikes(0)

Reply
- Jestine Yong
  
  June 5, 2020 at 2:24 pm
  
  Hi Vigneswaran,
  
  If only the capacitance range that can't be used, probably there is a small SMD fuse or low ohm resistor blown in the capacitor circuit.
  
  Jestine
  
  Likes(0)Dislikes(0)
  
  Reply