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Four IGBT Shorted On a Dead Welding Machine

By on June 11, 2020
how to fix welding machine














how to fix welding machine

It is a 200 amp welding machine that went dead and usually with this kind of machines if the IGBT get shorted, the whole machine will go dead. So I headed directly to these parts.

how to repair welding machine

As I took the screws off I was able to see what inside and machine and it looked brand new.

how to repair and fix welding machine

The first place to look was the IGBT’s located on this heat metal shield.

fixing welding machine

I could see four IGBT’s there and when I started testing them while on board, I got the indication that all four of them were shorted.

welding machine igbt shorted

And as expected, when I took them off board and tested them again, all four IGBT’s were shorted and needed replacement.

I called the customer to tell him my repair price and although I went as low as I can with the price, he did not agree.

repairing welding machine easily

Although the customer and I did not agree on the price, I went ahead and turned the machine on after disconnecting the pins of the IGBT’s from the board and as you can see, the machine was up and running.

There will be no voltages on the output of the machine terminals and because of that, no welding can be done. I just turned it on for a few seconds to make sure all is well. Anyway, the machine is still in my shop waiting for the customer to pick it up, until then be safe.

Mission Almost 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 repair articles in the link below:




  1. Bobby Y

    June 11, 2020 at 8:34 pm

    Hi Waleed, in cases like this what is the cause of the IGBT damage?
    Thank you.


    • Waleed Rishmawi

      June 13, 2020 at 4:36 pm

      Bobby: usually the cause for this damage is using this tiny machine beyond it actual power and never give this tiny machine a break from welding. in other words misusing the machine. have a blessed day

  2. Parasuraman S

    June 11, 2020 at 8:52 pm

    Very unfortunate that there is a customer, who wants to get things done, but do not want to pay for it! We should make a note and discourage such guys from bringing anything further for service! Such guys do not deserve any better treatment!

    • Albert van Bemmelen

      June 11, 2020 at 10:29 pm

      I totally agree with Parasuraman. The person who brought you this repair must understand that such a repair job takes time and not only time is money but also the 4 IGBT mosfets have to be paid for. And no one should have to accept such behavior from any customer. Any human being should act in a way that he would like to be treated himself. So in this case he only earned your disrespect.

      • Waleed Rishmawi

        June 13, 2020 at 4:42 pm

        Albert: totally agree with you there but there are a lot of customers like that sad to say. like we always say, he will try to get his machine fixed somewhere else. The other guy who repair welding machine other than myself is already aware of this guy and he is a close friend of mine. we are in control and the lesson will be taught the hard way. have a blessed day

    • Waleed Rishmawi

      June 13, 2020 at 4:38 pm

      Parasuraman: there are a lot of customers like that sad to say but on the other hand, since there are two people in our area who repair welding machines, I contact the other guy who is also a friend of mine to be alert for this guy. Have a blessed day

  3. Gregory B

    June 11, 2020 at 11:30 pm

    Maybe give the customer an estimate before you even start ... nice article ... thanjs

    • Waleed Rishmawi

      June 13, 2020 at 4:47 pm

      Gregory: you are most welcome but in our area of the world we do not deal with estimates sad to say. other good customers even if we do not agree on price, they are willingly paying for my time spent on finding the fault. I am building some kind of system with names of customers and their phone numbers and the history of their behaviour. this customer is on the bad list and his name is marked and well know now to all the technicians in the area. have a blessed day

  4. Gilberto

    June 12, 2020 at 12:41 am

    Lamentablemente eso conlleva a tener que cobrar por el diagnóstico y, si el cliente acepta la reparación, se descontará esa cuota del costo por ella.
    Gracias por compartir.
    Unfortunately, this leads to having to charge for the diagnosis and, if the client accepts the repair, this fee will be deducted from the cost.
    Thanks for sharing.

    • Waleed Rishmawi

      June 13, 2020 at 4:48 pm

      Gilberto: sad to say, estimate is not the way it is done here but we are working on it. have a blessed day

  5. Andrew F. Ali

    June 12, 2020 at 12:57 am

    Well done!! Sometimes we meet the odd Customer who will not agree with our price for repairs as they do not appreciate the level of intelligence is required to troubleshoot. They sometimes just want to find out what the problem is to repair it themselves. Sometimes too they just feel it easier to buy a new one. They sometimes forget time is money and you have an electric bill to pay as you would have used some electricity in troubleshooting. Good Luck and God Bless You.

    • Waleed Rishmawi

      June 13, 2020 at 4:50 pm

      Andrew: thanks man. yes, there a customers like that all over the world sad to say. This customer is on the black list in our area but soon..he will need something for repair.. have a good day

  6. Tayo

    June 12, 2020 at 1:31 am

    I think the customer thought (hoped) the repair would be simple and cheap. I doubt Waleed gave him an estimate on the repair costs before hand bcos he did not know for sure (although he had a pretty good guess that it was the IGBTs where were the culprit right off the bat). Before we jump on the customer's back perhaps we should ask how much the bill was for this repair. We all know that expertise like Waleed's isn't cheap. I actually would pay a premium to have a sticker on my appliance that reads "Repaired by Waleed!" 😀

    • Waleed Rishmawi

      June 13, 2020 at 4:56 pm

      Tayo: in our area we do not have the estimate repair cost sad to say. I gave him the cheapest repair cost but he still insisted on getting a cheaper repair cost. I thank you for your nice gesture and I appreciate the encouragement. have a good blessed day

  7. nkokana

    June 12, 2020 at 2:37 pm

    what a good job .sometimes the customer may think since the parts are cheaper hence the price should be lower yet not knowing what matters is to find the component that find what shorted is the most difficult of the repairing issue

  8. Waleed Rishmawi

    June 13, 2020 at 5:00 pm

    nkokana: Parts are not cheap and the labour is not easy either but I gave him the cheapest repair cost ever because he is a first time customer and I wanted to win him over. any way, have a blessed day


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