ESR Meter Add On to Detect Magnetic FieldBy Jestine Yong on May 23, 2014

 Hi Mr Jestine,

I would like to say thank you for all the good articles you have sent to me. I always remember your statement about “making things happen”. I found an idea when “playing” with my homemade ESR meter. This ESR Meter was based on Allan Willcox design. I made the enclosure from lunch box because I couldn’t find a nice box to buy over here. I use this meter with crocodile clips attach to my analog VOM set to 100micro Ampere in order to read the ESR ohm.

 

I have read your article “how to make full use of ESR meter” and I am trying to measure playstation stick vibration motor to see the result although you didn’t mention it on the article.

There was no deflection on my meter when checking on the motor winding. I think this motor acts like an inductor and if in good condition wouldn’t show low ESR ohms reading.

Another example of Vibration Motor

I have tested several good flyback and SMPS transformer windings with ESR meter and no deflection too. While trying to move the vibration motor I noticed that the ESR meter needle moved slightly.  I asked myself “what is this”? I began to think more deeply.

Based on my basic knowledge about motor, magnet, and inductor when inductor energized by electricity they create a magnetic field surround. There are magnets in the motor. Flyback, yoke and transformer is generating the magnetic field, and I think this would help me to identify them working or not when under operating with the help of my ESR meter.

First I tried to attach some magnet to ESR meter probes and moved it near some inductor or transformer that plugged in, nothing happened. I tried to attach some ferrite core to probes again and unfortunately still get no result. After a while of thinking, this ESR meter has 6mv p-p voltage and why not to make my own inductor probe and use it to search for the magnetic field. At first I just made an air inductor. I don’t have inductance meter to count henry values but my ESR meter showed about 25ohms when attach with this inductor. I move it to the magnet and guess what? The needle was deflecting.

I want to test on SMPS transformer but I am afraid because it was non insulated so I tried to make it on bolpoint tube and insulated it with a bigger tube. I closed the top of the tube with sealed acid battery rubber cap and insulated the cable with heat shrink. After that I closed this heat shrink with spark plug motorcycle rubber.

 

It is the time to prove this “add on” worked and first I have tried it on ATX Power supply and the needle moved back and forth when I moved this add on near the power transformer.

 

Second, I’d tried it on Monitor flyback and the result was the needle just moved once and back to 25 ohms value. Had tried it on the power section SMPS transformer the needle moved back and forward. So I concluded the working flyback and transformer will attract the needle to move back and forward. I have tested several Monitor and TVs, and the result was the same. When the transformer or flyback isn’t good or not energized, there will be no deflection on the needle. I guess this will work on another ESR Meter. From the test, a good working flyback, yoke and SMPS transformer will have about 4 ESR ohms. If close enough, sometime the needle will move toward negative ESR value ohms.

For some inductors, the needle just moves slightly back and forward. You have to make sure the needle is moving towards lower ESR value and back again. This proves the transformer or flyback generate a voltage and have a magnetic field around it. Since I am not an engineer I couldn’t explain in great details. I will be glad if others could explain and suggest an explanation.

 

If you want to build this, make sure the inductor is well insulated and stick it to long plastic tube to avoid your hand touching another component when probing, no need to touch this inductor, just moving it near flyback and transformer. I will take no responsible if you got electrocuted because of lack of knowledge to handle high voltage section on Monitor or TV and damage your ESR Meter when you accidentally connect this to high voltage.

With this article I hope I could help others to troubleshoot Monitor or TV faults especially on SMPS transformer or flyback with this simple add on. I haven’t tested it yet on LCD monitor inverter transformer, but this is more likely will work too.

After all, I have found ESR Meter and Ring Tester really save my time and easy to find the fault without guess work. I strongly suggest you to buy these two testers. I hope you don’t get bored with this article and I want to say this “I wouldn’t do a repair job without having an ESR Meter and Ring Tester on my hand”.  By the way you can buy a ready made Blue ESR Meter and Blue Ring Tester from Mr Jestine.

Note: I have found several flybacks that give a strong magnetic field than the others and the needle of my ESR meter deflect towards zero fast and could be broken. We can make the inductance value higher with more turns to prevent the problem because most ESR meter operated on 100kHz and read inductance significant. I think the best is in Milihenry range. My inductor seems to have about 30 Microhenry because it just read about 25 ohms on my ESR meter.

Best Regards,

Rudi Wijaya

This article is contributed by Rudi Wijaya from North Sumatera Medan (Indonesia). He is an electronics repair hobbyist and specializes in TV, Monitor and DVD repair. He usually repairs the items that belong to friends and family.

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