Two K50T60 Mosfet Burnt
My brother, who in the welding business brought this to my shop, His shop is right next to mine. He did not know what happened to it but suddenly, it stopped working. When I powered up the machine, I could hear something rapidly ticking inside.
I took the cover off and got the main power board.
I powered it again, and the ticking noise was coming from the main power relay of the machine.
This is a close up of the black relay that was ticking.
I flipped the board and I checked the main pins of the relay, they were fine. I measured the power reaching the relay and it was fluctuating. I took the relay and tested it with a 24 volts power supply, it checked out bad so I replaced that part with this one. 24 volts and 30 amps relay. Same specification yet different look.
I powered the machine and the ticking stopped but it was not welding and the yellow light came on indicating either over heating or shorted Mosfets.
I was about to check the Mosfets, when I saw this damage.
I saw this and right away, I knew there was something wrong with the main Mosfets. The damage that you see in the phone is connected directly to the Mosfets beneath it. Take a look
That is one of the Mosfets.
And here is the second one. It was K50T60 Mosfets
I found the exact replacement at my shop. I replaced both after cleaning and connecting the bad lines on the main board.
Once it was put together, I was ready to test the output on the machine.
As you can see, the protection yellow light was off and only the power indicator was working. I tested the DC output voltages, well, check out the photo:
It was a challenge but it will be fixed if you put your mind to it. 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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Jestine Yong works as an Electronics Repair Lecturer in Kuala Lumpur Malaysia and his training website is http://www.NoahtechElectronicsTraining.com. You can check out his repair blog at http://www.JestineYong.com
16 comments on “Two K50T60 Mosfet Burnt”
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Nice repair Waleed! I wonder if the Relay was protecting the defect PCB from further damage?
The relay was not getting the right voltage to work..
Good job, Waleed. The resistor next to the relay isn’t looking very well.
Yea I saw that but it works fine.
Great article, appreciate your help. I was just wondering what you think the future of electronic repair is, and whether electronic components and repair will be very different in 20 years time.
Hi Futurethink,
I guess it would be getting much more smaller than now the components for the motherboard and for power supply it will get smaller in thickness (height).
Jestine
supperrr
Good Repairing Mr.Waleed.
excellent wallid
Excellent work! Very badly damaged, but brought back to working condition! That’s great!
What can cause microwave oven to emit sparks even after sray painting it?
Good job! Waleed.
I have a problem.
in homeage ups.
the relay clicking.
at back up mode it is ok.
but when at ac it is cliking sound by relay. any suggestions
Have very similar welder Hugong mig stick180 pcb board looks identical, on mine all four mosfets shorted can’t figure out why and also can not find replacement k50t60 mosfets only igbt with same part number and board pin out shows mosfet GDS any help or advice would be greatly appreciated welder has less than three hours use on it.Thankyou in advance
Mark: mosfets Or IGBT’s usually shorted out by default or something caused them to be shorted. sometime a miss use of the machine can cause them to short out. a lot of welding techinicans use these machine on power Generators and that is not healtly for for the welding machines.
the only source I get these is on line off Ali express or any other selles who deal which surch parts.
have a blessed day
Thanks, have looked on Ali express all that I can find with that part number are igbt nothing in mosfet and pin out and schematic symbol shows mosfet