IGBT Transistor Shorted In Welding Machine
A welding technician brought his dead welding machine for repair. It has been a long time since I repaired such machine because of Covid 19 situation. Not many welding shops are open like they used to and that is really bad.
The screws were already off and that is a clear indication that someone tried to fix the machine.
The customer explained that his brother tried to fix it and that brother has no knowledge of electronics repair and that worried me a bit.
The first thing that I saw was this; it was supposed to be a PTC part there to act like a fuse but instead I found a varistor there. I took that part off and replaced it with the proper PTC and headed directly to the IGBT’s on this machine.
As expected, IGBT part was shorted to all three pins which indicates a serious issue in this device. The part number is 60N60FD1. If this one was shorted, I was very sure that the other part similar to this is shorted as well.
And as expected the other part was shorted as well and needed new replacement.
I replaced the first one and the second one but I was still worried to power on the machine. I did further checking around this area but I was lucky not to find any more shorted components.
I powered it on but through a current limiter homemade device and hoped for the best.
As you can see in the photo, the power LED light was on and I was getting DC voltages reading to the positive and the negative terminals of the welding machine.
I was happy to see that and a kind of relief on my part. The customer with his brother came to pick up the machine. The brother had so many questions to ask but I do not think he understood what I saying and that is normal because he does not have any basic knowledge about electronics. Anyways, the machine was up and running and that what counts.
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 repair articles in the link below:
https://jestineyong.com/a-drill-battery-charger-was-powering-on-but-does-not-charge-repaired/
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Parasuraman S
December 21, 2020 at 9:38 pm
Another well done work on a welding machine! Yes, you are right! The snoopy meddling in an electronic equipment is a big headache. But in this case, anyhow, the customer told the truth! Recommend him to undergo a training with Jestine Yong! He will be alright! (LOL)
Waleed Rishmawi
December 22, 2020 at 2:37 am
Parasuraman. That is a good advise. But your are right he was honest to tell me what was going on with the machine. Have a good day
Albert van Bemmelen
December 21, 2020 at 10:38 pm
Good job of course, but I wondered how you were able to know what was the right PTC for this board. Or is it a standard value component that acts as fuse as you said?
Waleed Rishmawi
December 22, 2020 at 2:34 am
Albert: the guy who was messing with the machine brought it to me. I had also the same machine in my shop. Have a good day
Jaikumar Bidkar
December 22, 2020 at 2:40 am
It's very nice work, because working with IGBT type parts it's always been risky when someone else not checked full circuitry for any damage like small pf, smd diodes, resistors, zeners, on PC for open or shorts or high valued, that'll cause more problems after replacing new IGBT, LIKE THE WHOLE WORK VERY MUCH, THANKS FOR SHARING.
Waleed Rishmawi
December 22, 2020 at 7:11 pm
Jaikumar: I am glad you enjoyed the article and the work done on the welding machine. have a blessed day
Humberto
December 22, 2020 at 2:33 pm
Good repair. Thanks for sharing your expertises.
Waleed Rishmawi
December 22, 2020 at 7:12 pm
Humberto: thanks man. long time I did not hear from you. I hope all is well. you are most welcome m y friend. have a blessed day
Yogesh Panchal
December 23, 2020 at 4:03 pm
Welding Machine Repair Doctor well done!waleed
Waleed Rishmawi
December 23, 2020 at 9:18 pm
Yogesh: thanks man for the nice gesture. have a blessed day
vikas
January 17, 2021 at 3:34 am
Do you have a schematic of this machine?