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IGBT and Industrial Bridge Rectifier Shorted

By on September 29, 2021

The machine was donated to me about two months ago because the customer thought it was too expensive to be repaired so he went and bought a new machine instead.

welding machine repair

I was planning to dismantle the machine and use it for parts but today I decided to get it fixed and if I find a buyer I would sell right away.

industrial bridge rectifier

The first thing to deal with was the bridge rectifier (industrial type) because it was already shorted.

Once that part was replaced I headed to other blown parts in the machine.

igbt shorted

igbt 30n60a4

Click on the photo above to access the G30N60A4 Datasheet

There were two IGBT’s that were shorted and right away I went ahead and replaced these two blown parts in this machine.

dry joints in pcb

The last fault to take care off was the loose connection of this cable which is connected directly to the positive output welding terminal of the device.

I believe this was the damage cause found in this device because I found sparks and arching marks inside.

solder joints in pcb

I cleaned that area and re soldered it and I was ready to test out the machine. So I put it all back together and gave it a try.

how to test welding machine dc voltage

I connected it to a current limiter and powered on the machine. The voltages were coming out as expected. The negative reading you see on that meter because I got my multi meter probes reversed but everything was according to specs once it was tested at my brother’s shop.

Now I am going sit and wait for the right customer to come in and hope for the best.

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 Massage Device Repair



  1. Albert van Bemmelen

    September 29, 2021 at 1:27 pm

    If it is about igbt mosfets and stuff it only can be an article from the one and only Welder repair engineer Waleed! And thanks for another mosfet datasheet!

    • Waleed Rishmawi

      September 29, 2021 at 4:12 pm

      Albert: thanks man. I appreciate your comment. have a bleseed day

  2. Elisha

    September 29, 2021 at 1:44 pm

    What is a current limiter. Thanks

    • Waleed Rishmawi

      September 29, 2021 at 4:14 pm

      Elisha: a current limiter is a light bulb connected to the main fuse of the device. you can check them out and build one off the net. once you build a device, the fuse will be in the machine while connecting the whole machine to this device. have a blessed day

  3. Yogesh Panchal

    September 29, 2021 at 2:54 pm

    Good repair!
    Are this machines having Variable voltage & ampere??

  4. Mark

    September 29, 2021 at 3:42 pm

    Well done Waleed!
    Another welder, but at least this time, hopefully you can sell it and have the satisfaction of the repair as well as a little more in your wallet!

    • Waleed Rishmawi

      September 29, 2021 at 7:35 pm

      Mark: thanks man. yes, I already sold the machine and a have a lot more in the pocket. have a blessed day

  5. Waleed Rishmawi

    September 29, 2021 at 4:18 pm

    Yogesh: these machine????? you mean welding machines? the input voltage is usually 220 AC volts but the output is a varialbe DC voltage. they have an amp variable pot and you can adjust the amp to the rate needed for welding. have a blessed day

  6. Parasuraman S

    September 29, 2021 at 4:20 pm

    Guess it is another Welding Machine, as you do not mention it anywhere. Good repair! You have one standby now, which you can give for hire!

    • Waleed Rishmawi

      September 29, 2021 at 7:37 pm

      Parasuraman: yes, it has been a while but yes, I do have a lot of fun mixed with a big challange when doing these machines. the machine is not on standby, I already sold it for a very good price. have a blessed day

  7. Babu M S

    September 29, 2021 at 9:47 pm

    your master in welding machine repair and proved any condition welding machine you put back in to service. Thank you very much for sharing.

    • Waleed Rishmawi

      October 1, 2021 at 2:18 pm

      Bahu: you are most welcome. I thank you for your nice comments and be blessed today.


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