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Question About Blue Ring Tester

By on September 7, 2008

blue ring tester

I received an email today from a member who asked about the accuracy of Blue Ring Tester in testing coils. Here is the question:

“Today I have repair a Sanyo Flat Screen Color TV which has a Pincushion problem at first i check the output transistor and check ok and second i check two pincushion coil with the blue ring tester, because the plastic which wrap around the coil has a little bit deform, but when I check it with the blue ring tester it taste bad no LED Light. the i try to replace the two coil but it the the pincushion problem is still there. Further investigation reveal that one of the signal diode was shorted and replacing the diode solve the pincushion problem.What I mean was this why the Blue ring tester cannot detect if the coil is good or bad when you always say it can detect. I had no problem with the ESR meter I agree with you but not the Blue ring cannot tell me whether if there is a short or not.Can you tell me?”

Hi D,

If you refer to my website at especially on the tester specification, you would see that i mentioned four types of coils i.e B+ coil, smps primary winding, horizontal yoke coil and flyback primary winding coil. I didn’t mention the pincushion coil, horizontal size coil and horizontal linearity coil was because the inductance value were quite low. That means if the coil has a core that have only little loops (windings) in it then we cannot expect the blue ring tester to show full LED and etc. If the inductance value is low we can only expect low or no LED lit. If the inductance value is high then we can expect it to register some reading of LED lit. In other words, the higher the inductance value of a coil, the higher LED of the Blue Ring Tester will light up. A high inductance value coil that have shorted turns will cause the LED light to go low or no light at all.




  1. Gerry Millward

    April 2, 2009 at 11:44 pm

    Presumably, if the coil shows a low result (few red or no lights at all), you should check it again after removing it from the circuit to ensure that this wasn't due to another faulty component shorting (or partially shorting) the coil?

  2. admin

    April 3, 2009 at 7:31 pm

    HI Gerry,

    Yes you are right and should check it off board if you check on board and found the coil shows Red LED's but again it depends on what type of coil you are checking. Some coils that has less turns tends to have less LED's lights up.


  3. Johan

    March 9, 2011 at 3:28 am

    Hi Jestine. I just recieved my Blue Ring Tester from you and thanks for this great tester. I have just managed to repair some LCD Computer Monitors and if it was not for this tester it would have been a case of trial and error. Thanks again.
    South Africa

  4. admin

    March 9, 2011 at 6:19 am

    HI Johan,

    Good to hear that you have success in repairing the LCD Monitor using Blue Ring Tester.


  5. Vuqar

    June 4, 2011 at 8:37 am

    bizde Blue Ring Tester almaq istiyoruz nasil yardim ede bilersiniz?

  6. admin

    June 4, 2011 at 9:11 pm


    Eğer bana para göndermek için Western Union para veya gram kullanabilirsiniz. eğer ilgilendi sana banka bilgileri göndereceğiz.



  7. Andre

    August 28, 2014 at 4:06 am

    Hi jestine were can I buy a blue ring tester. I am from south Africa. Regards Andre

    • Jestine Yong

      August 28, 2014 at 10:01 pm

      Hi Andre,

      I have sent a personal email to you.



      • Robert

        August 29, 2014 at 5:02 pm

        Hi Mr. Yong,
        I wish I would have bought the kit for the Blue ESR meter instead of the assembled unit from Anatek. I still forget sometimes that companies now use non-leaded solder!
        Also, the PCB is just so cheap looking because the components are soldered in all crooked and mangled looking. If I were Anatek, I'd be embarrassed to send someone such a unit.
        From now on, anytime I can get something in kit form, that's what I'm going to get. They charge $24 for assembling that's only worth $3! If the assembled Blue ESR meter would have been the first meter I bought from them, I would have never bought anything else from them.

        • Robert

          August 29, 2014 at 5:11 pm

          Oh, sorry. I thought this article was about the Blue ESR meter.
          I bought my Blue Ring Tester in kit form and built it myself. My work building it is absolutely beautiful.


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