A Shorted Mosfet 2SK2837 Found In Welding Machine
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.
It is a beat up welding machine on the outside but on the inside the condition of it was much better.
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.
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.
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.
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
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).
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 York Treadmill Error E1 Repair