Don't Miss

Shorted IGBT 60T65PES

By on March 13, 2020
welding machine repair








A technician and a friend of mine called me and asked some questions about welding machine repairs. As this tech explained that the welding machine he was working on was completely dead and he needed some repair hints to get it fixed. I tried to explain as much as possible but at the end of our conversation, he decided to send it to me for repair.

welding machine repair moller

It is a 200 amp welding machine that supposedly made in Germany but as you can see, it was completely dead and need some tender loving care.

As I took the top cover off and I could see that there is no way this machine was made in Germany as it was labeled on the front cover. It was a cheap China made welding machine that hardly cost anything to be made.

welding machine fix moller

The two welding terminals connections are supposed to be made of copper but as you can see the white metal, that was not copper. Any ways, let the repair begins.

fixing moller welding machine

I checked the bridge rectifier and was not shorted and my next step was the IGBT’s on this welding machine.

igbt shorted

Two screws were holing the heat sync to the board and as I took them off and soldered the pins of the IGBT, I was able to test the part and find out that both parts were shorted out and needed replacement.  The part number: 60T65PES.

igbt shorted and burned

If you look to the multi meter reading, the IGBT was shorted on all its pins which mean I have to check all the component around it just to make sure nothing was burnt or shorted.


Sad to say, I did not have this part available in my shop but when I checked for the equivalent part for it, I found it was FGH60N60SMD which I have in the shop and that put a smile on my face. 

I checked around these shorted parts for shorted components and it seems like nothing was shorted, open or out of the order, so I went ahead with the replacement of these two IGBT’s. I powered the welding machine on and to my surprise, the machine started to vibrate so I turned the machine off right away and checked for the cause of this vibrations.

fan vibration welding machine repair

One of the fins on this fan was broken so when the fan turns, it vibrates the whole machine so a replacement was due for this device.

fan problem in welding machine moller

I found the right fan replacement for this machine because if I replace the two IGBT’s and did not replace the fan, the IGBT’s will end up heating up and the welding machine will die again.

how to fix and repair moller welding machine

I turned the welding machine on and I was getting the right voltages. From past experience, getting the right voltages on the output of the machine does not mean the machine is up and running so I took it to my brother who is a welder and gave it a test. It was working like a charm.

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.

P.S- Do you know of any your friends who would benefit from this content that you are reading now? If so, forward this website to your friends or you can invite your friends to subscribe to my newsletter for free in this Link.

Note: You can check his previous repair articles in the link below:




  1. Parasuraman S

    March 13, 2020 at 5:51 pm

    The world expert on welding machine got another interesting job to fix! Well done!

    • Waleed Rishmawi

      March 13, 2020 at 11:32 pm

      Parasuraman: and I thank you for your nice comments and encouragement. have a blessed safe day

  2. Albert van Bemmelen

    March 13, 2020 at 8:06 pm

    Parasuraman is right that not many experts could say the same!

  3. Waleed Rishmawi

    March 13, 2020 at 11:33 pm

    Albert: thank you and have a blessed safe day.

  4. Henrique J. G. Ulbrich

    March 13, 2020 at 11:51 pm

    A beautiful maintenance work, Waleed. Thanks for sharing. You´ve said that one fin was missing, but the picture show absence of two fins.

    • Waleed Rishmawi

      March 14, 2020 at 2:20 pm

      Henrique: I thank you for your nice comments. it could be one fin or two but the point the fan was broken and it got repaired. have a blessed day

  5. Gassan Ali

    March 14, 2020 at 4:06 am

    Interesting repair! I'm learning a lot about IGBTs from you, Waleed. I guess the fan was the initial cause for the IGBTs to go short.

  6. Waleed Rishmawi

    March 14, 2020 at 2:22 pm

    Gassan: thank you. I am glad you are learning about IGBT's. they are a lot of videos on youtube that can give you a lot of information about them. they are very interesting and learning about them would help you or any technician to repair things..have a blessed day

  7. Yogesh Panchal

    March 14, 2020 at 3:38 pm

    Good job! Waleed,

    What are basic output voltage of this type of machine?

    • Waleed Rishmawi

      March 16, 2020 at 6:36 pm

      Yogesh: thank you very much. it depends on the size. they is no basific voltage reading. some machines 60, some 80 and bigger machines usually 120 volts. but from experience getting the voltages on the output does not mean the machine is working out fine. it has to be tested by doing the actual welding on the machine to find out. have a blessed day

  8. Andrea Del Corso

    March 17, 2020 at 11:06 pm

    A good repairing ,compliment|

  9. jkim machona

    October 3, 2020 at 6:12 am

    could you pliz help me out mr Waleed Rishmawi . am facing a challenge on repairing a welding machine . it only welds for a very short time and goes on protect mode . checked all IGBTs are reading ok checked all components on main board are ok


Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.