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A Shorted Mosfet 2SK2837 Found In Welding Machine 

By on June 28, 2021
2sk2837 fet shorted

This machine was brought to my shop for repair by a welding technician but was put on my shelf for a while till I get the ok from the customer to go ahead with the repair.

how to fix welding machine

It is a beat up welding machine on the outside but on the inside the condition of it was much better.

fixing welding machine

If you look closely to the red LED light, you could see a very dim display of light which is an indication of a shorted component inside.

That light is a part of a protecting circuit kicking in to protect the machine from further damage.

how to repair shorted welding machine

I took the metal cover of and right away I could see the main brain of the machine and at the same time I could see some shinny soldering joints there. Someone has been in this machine but for some reason the technician thought that re soldering these point will bring the machine back to life.

Well, he started on the right track but did not continue because when I measured these points which are diode measurement, the bottom left side of the board gave me a short reading and that told me to head to the Mosfets for check up.

shorted 2sk2837 fet

Right away I found the shorted Mosfet and took it out of the circuit and when I checked that main brain of the machine, the short was gone.

2sk2837 fet shorted replace

2sk2837 datasheet

Please click on this link or the above photo to access the 2SK2837 datasheet

One shorted Mosfet could affect the whole operation of the welding machine and when I replaced this with a working new Mosfet, the machine was up and running. Take a look

dc output voltage of welding machine

We all know by now that when there are voltage readings coming out of the negative and the positive terminals of the machine is a very good sign but to confirm the operation I did some welding tests on it (that is the first time I do that, usually my brother who is a welder does for me).


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 article on York Treadmill Error E1 Repair



  1. Tayo

    June 28, 2021 at 11:21 am

    I thought you said it looked better on the inside. 😛

    Well done.
    Would you say that most of the issues with welding machines comes down to the MOSFETs.

    • Waleed Rishmawi

      June 28, 2021 at 7:21 pm

      Tayo: yes it looked better but not the best. LOL. yes, I would say it is about 85 percent usually the fault is Mosfet but sometime I get the main board fried but that hardly every happens...have a blessed day

  2. Albert van Bemmelen

    June 28, 2021 at 2:05 pm

    Another Mosfet you successfully replaced! There must be a growing number of different Mosfets out there you need to replace the bad ones with.

    • Waleed Rishmawi

      June 28, 2021 at 7:23 pm

      Albert: indeed and every machine has different Mosfets so I am up on my toes finding these parts and making them available in my shop. have a blessed day

  3. Yogesh Panchal

    June 28, 2021 at 4:23 pm

    Good Job! Waleed

    • Waleed Rishmawi

      June 28, 2021 at 7:24 pm

      Yogesh: thanks man. have a blessed day

  4. Parasuraman S

    June 28, 2021 at 4:59 pm

    Good job there and mission accomplished! Well done!

    • Waleed Rishmawi

      June 28, 2021 at 7:24 pm

      Parasuraman: thanks man. have a blessed day

  5. Ken

    June 28, 2021 at 7:23 pm

    How do you test the Mosfet in circuit to see if it shorting
    Regards Ken Sparkes Zimbabwe

    • Waleed Rishmawi

      July 2, 2021 at 5:10 pm

      Ken: test the Mosfet in circuit? usually will read short in all pins but it is better to test it off board. in my case I developed a way to check it in welding machine through testing the main board that is connected directly to these Mosfets. for more details on checking Mosfet, you can search it on google..have a blessed day

  6. Anwar Y Shiekh

    June 29, 2021 at 9:19 pm

    How many welding machines are out there? you seem to be fixing a lot.

    • Waleed Rishmawi

      July 2, 2021 at 5:13 pm

      Anwar: there are tones of welding machines out there but they all work the same way. there are a lot of welding machines that has different brand names yet on the inside they have the same exact boards and parts. some machines have different Mosfets parts numbers so I have to keep up with these parts and keep them available in my shop to do these repairs. have a blessed day


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