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AC Stabilizer Repair

By on May 22, 2015
ac stabilizer repair










My mother called me that her Air conditioner was not working. After work I went straight home and took my tool kit to check the air conditioner. The air conditioner was not getting power from the ac Stabilizer. So the real problem was the stabilizer and not the air conditioner. The ac stabilizer was very old (more than 10 years) with the model by the name of Syscom and rated 4KV. Take a look at the photo below:

ac stabilizer repair

All the three LED indicators were not lighting up when the stabilizer was switched On. So I opened the top cover to inspect what may be the reason.

The power supply was reaching the relay but no further. I saw a burnt mark at the side of the relay and instantly I know that it was the root cause of the failure.

burnt relay

ac stabilizer repairing

Photograph of faulty relay can be seen in the below picture. There were total three relays and two relays were defective.

bad relay

Since it was already late so I decided to buy the relay the next morning. After breakfast I went to the electronic shop which was located about 6 Km away from my home. I got new relays for about INR 40.00 each (about USD0.70).

 ac stabilizer repair new relay

I replaced it with the new relays and voila the ac stabilizer was back to life once again.

ac stabilizer repairs

 ac stabilizer repairings

Mission accomplished.


This article was contributed by Doraiswamy SR from Chennai India. Served  in Air Force as  an Electronics Engineer for 20 years, presently working as Manager in a manufacturing factory. An electrical and electronics enthusiasts undertakes repair and rectification job as a hobby and to learn more.

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  1. Dan Graham

    May 22, 2015 at 12:21 pm

    I purchased your eBooks. I read your emails and enjoy them. No time to do many repairs but have learned a lot. I sometimes do electronic repairs and what I learn here is very helpful.

    • Jestine Yong

      May 22, 2015 at 2:24 pm

      HI Dan,

      You are welcome and glad that you have learned a lot from this site. And need to thanks to those who had contributed the articles also.


  2. Robert Calk

    May 22, 2015 at 12:33 pm

    Good job Doraiswamy. I'm glad your mother has her AC working now.

  3. Yogesh Panchal

    May 22, 2015 at 2:44 pm

    Good article please keep sharing your repair experience.

  4. Biruk Aweke

    May 22, 2015 at 3:28 pm

    HI good work thanks for sharing.

  5. Amir Mukhtar

    May 22, 2015 at 3:49 pm

    Thanks you Mr. Doraiswamy to share informable article.

    Keep sharing your expertise to learn more easily.

    Amir Mukhtar AShrafi

  6. Albert

    May 22, 2015 at 7:56 pm

    Hi Doraiswamy,
    Your replacement Relays really don't cost much since they are sturdy 30A/20A current types for 250VAC. (Normally Open /Normally Closed contacts).
    When those relays in future aren't available anymore, you always can replace them by modern Solid State Relays. They are more robust and failproof. It is always a good feeling knowing you were able to fix important equipment at home.


    • doraiswamy

      May 23, 2015 at 4:26 pm

      thanks for the tip... will keep in mind..

  7. Humberto

    May 23, 2015 at 1:37 am

    Good repair Mr. Doraiswamy. Congratulations.

  8. Florin

    May 23, 2015 at 2:18 am

    I don't see why it was important to know how far was the electronics shop or who is the owner of the defective part. Too much personal data. This is not Facebook.

    Try this: "I had to repair an AC stabilizer. I measured it and found 2 bad relays. I bought and replaced them. Job done. See photos."

    • Jestine Yong

      May 23, 2015 at 5:04 pm

      Hi Florin,

      Every writers has their own ways of writing style. They can write like a story, short description, point form, few paragraphs and etc. I suggest that why not you try to write your repair article and post it here and let other comment about your work.


      • Askia

        October 24, 2017 at 11:38 pm

        please sir i have an automatic voltage regulator stabilizer the unusal red light is on and the delay light is also blinking,please what will be the problem with the stabilizer thanks.

  9. Emiliano Briceño

    May 23, 2015 at 9:25 am

    Thanks , from Venezuela , good articles .

  10. Abdul

    May 23, 2015 at 2:08 pm

    Thanks for the informative article keep sharing.
    From Singapore.

  11. Andile

    May 24, 2015 at 9:49 am

    Great Job

  12. mahmoud_tajpour

    May 25, 2015 at 4:55 am

    hi dear jestine I must thank you that cause severe a lot of good information byy the engineers and technicians and repairmens send to each other.

    • Jestine Yong

      May 25, 2015 at 8:30 am

      Hi Mahmoud,

      You are welcome.


  13. reza

    May 28, 2015 at 8:05 pm

    hello mr Doraiswamy SR
    thank u

  14. Loveday

    March 15, 2017 at 6:19 am

    How would one know a faulty relay in a stabilizer

  15. Loveday

    March 15, 2017 at 6:23 am

    I have a stabilizer that after the delay light blicks for short time and switches out the output; it stays for short time and trips off again. The unusual red light starts blinking. I changed the output relays... But.. It still continues. Please i need ur help. What could be the cause or the faulty component in it..?

  16. Saheed Quadri

    December 4, 2017 at 12:49 am

    Input -100-260
    Output -220v+-6%
    Model -cvr1088-1000va
    Ac AVR.
    I am engineering students, I used to work on electrical / electronics equipments and God always help me. there is this stabilizer with above details, It has two meters input and output, the input show 220v but output read zero. please guide me

  17. Gera

    August 4, 2019 at 5:02 am

    Hy Florin,
    What might not be useful to you might be useful to others.
    If you don't mind, Florin,Master young's suggestion might help you.

  18. Ismail

    April 6, 2023 at 4:06 am

    Please sir ,if input of a stabilizer is reading zero and the output is working perfectly, what could be the reason? thanks!


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