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Shorted IGBT In A Welding Machine Replaced

By on December 17, 2021
welding machine repair







A welding technician brought this welding machine for repair. As I understood it from the guy, the machine was welding fine then it went into shut down. He tried to connect it to a different power source but was no use.

igbt welding machine repair

The customer also made a remark that the Overheat light indicator was going on and off and then it went into shut down.

That was a good remark and based on that, I headed directly to the IGBT and I am almost sure there lays the problem.

ingco welding machine fix

I tested for short there and as expected, the meter indicated a short in the area of the IGBT and based on that I took the first heat sink out for further testing.

igbt testing welder machine

The main power switch has to be taken out as well so I can reach the other shorted IGBT there.

how to fix igbt

Both heat sinks holding the 4 IGBT were taken out and my testing was confirmed.

shorted igbt transistor

Two IGBT out of four were shorted but from experience, it is better to replace all four and that is exactly what I did.

Part number FGH60N60

FGH60N60 datasheet

You can click here or the above photo to access FGH60N60 datasheet

FGH60N60 fluke test

As seen in the previous photo, I replaced all Four with the same exact part number and then powered up the machine. The reading you see on the meter is low because the machine was connected to my current limiter but when connected to power without the current limiter, the reading was almost 60 DC volts. Of course I never give it to the customer without the actual test of welding so I took it next door and gave it to my brother the welder and gave it a try. It was working according to specs.

Mission Accomplished.


This article was prepared for you by Waleed Rishmawi, one of our ‘Master Authors’ and currently working in the Bethlehem area of Palestine repairing electrical and electronic equipment.

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Note: You can check his previous article on A Cheap Bluetooth Speaker With Ripped Charging Ports Repaired




  1. Albert van Bemmelen

    December 17, 2021 at 9:36 pm

    The number of already by you fixed Welding machines must have reached a enormous amount of devices by now I guess? And again thanks for showing another IGBT datasheet!

    • Waleed Rishmawi

      December 18, 2021 at 4:58 pm

      Albert: yes, I have fixed a lot of welding machines that I lost count. as I was told by the recenet customer, you are well known in the area which makes me glad. have a blessed day

  2. Lazarus Dsouza

    December 17, 2021 at 9:40 pm

    Thanks so much !

    • Waleed Rishmawi

      December 18, 2021 at 4:58 pm

      Lazarus: you are most welcome

  3. Eric Rice

    December 17, 2021 at 10:38 pm

    It’s good to see you fixed it, but was the actual cause? Did a fan stop working? Did dirt create a circuit to cause the short? Just wondering.

    Thanks for the article.

    • Waleed Rishmawi

      December 18, 2021 at 5:02 pm

      Eric: the cause varies from one machine to another and the way it was used by the technician. in this case, the one who replaced the negative and positive terminals of the welding machine did a bad job. the customer wanted me to replace them but we did not agree on the price so he send it to another repair guy for cheaper replacement and that was the outcome of the customer being cheap to pay the righ price. have a blessed day

      • Eric Rice

        December 18, 2021 at 9:12 pm

        Thank you for your reply. I repair vacuum tube audio equipment, and I’ve seen a lot of rank repair from other repair shops and customers trying to repair their own gear. I’m not the most expensive, but like yourself I try to be fair and up front about cost and I don’t want anything coming back or someone else saying I do poor work! Good job Waleed and indeed you have blessed me today. May the Lord bless you as well.

        • Waleed Rishmawi

          December 20, 2021 at 3:28 pm

          Eric: you are most welcome. I apprecite your comment.

  4. Parasuraman S

    December 18, 2021 at 8:44 pm

    I am sure you would have crossed a few centuries of repairing these welding machines! Great!

    • Waleed Rishmawi

      December 20, 2021 at 3:30 pm

      Parasuraman: I have seen a lot of them these past years and I lost count. not many people fix welding machines in my area but I do my best to repair all of them although sometime I think that is almost impossible. have a blessed day

  5. Elisha Melvin

    December 18, 2021 at 11:20 pm

    Thank you sir. But I have got two questions.
    1.How do you test for a defective IGBT(shorted).

    2. What's a current limiter u used with your DMM

    • Waleed Rishmawi

      December 20, 2021 at 3:37 pm

      Elsha: usually the IGBT's are connected to the main brain of the machine and therfore there are two ways to do it on and off board. the first is to check the main pin connector of the main board ( usually four points) using a doide setting and the second way is to disconnect them off board and do a diode testing there.
      I have built a current limiter using an idea found on youtube. i have used a light bulb, a power switch and a power outlet. search it on youtube, it is a good tool to have in the shop. have a blessed day

  6. Amir Mukhtar AShrafi

    December 20, 2021 at 6:06 pm

    Well done
    thanks for share good experiences.

    Best of Luck

    Amir Mukhtar

  7. Yogesh Panchal

    December 20, 2021 at 7:02 pm

    Congratulations! for another fix waleed

    • Waleed Rishmawi

      December 21, 2021 at 2:40 pm

      Yogesh: thanks man. you are most welcome

  8. Humberto

    January 15, 2022 at 12:40 am

    Another Welding Machine repaired, you have fixed lots of them. You are a Master in this field


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