A Welding Machine Powers On But Does Not Welled Repaired
A regular customer brought this welding machine for repair and according to what I saw when I powered it on, (power switch was not active) there was either a short or some overheating going on inside the machine. Let us find out what kind of fault was it.
According to specs, the green light is suppose to come on as an indication that the machine was on but the red right is not suppose to come on unless there is a fault going on inside the machine and that is for protection.
Usually when I see this kind of fault, I usually head to the main Mosfets and look for shorts there but to my shock all Mosfets checked out fine.
While I was checking inside this machine, I saw this; someone was inside this machine and actually disconnected the power switch and connected the main power wires directly to the main power board.
That explained why the power switch was not active when I first power up the machine.
As I was checking the welding boost circuit which is connected to the main Mosfets, I saw this. The two red wires melted and shorted together and that explained why this machine indicator was showing a short inside the machine. One of the red wires was also loose not completing the welding loop.
The black and red wires are connected to the welding transformers that sit beneath the heat metal of the Mosfets. When testing the black and red, it was showing a low resistance and that is what I am supposed to get on both transformers.
Since the two red wires were shorted together, the machine was protecting itself by indicating a red over heat signal not allowing the machine to go ahead with the welding process.
As you see in the photo, a surgery was done there to bring the welding machine back to life.
The moment I separated the two shorted red wires and repaired the fault, the overheating indicator was back to normal and because of that I was getting a normal voltages are the positive and negative terminals of the welding machine.
The customer insisted not to install a power switch against my recommendation due to the fact the power switch always fails and constantly has to replace it. I offered to install a higher amp rated switch free of charge but still he did not agree. It is good idea to have a power switch to on and off the machine while it is connected to AC source. It is his decision and he will take responsibility for 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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Note: You can check his previous repair articles in the link below:
https://jestineyong.com/corrosion-in-rechargeable-batteries/
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Yogesh Panchal
April 6, 2020 at 4:20 pm
waleed,
welding equipment specialist clap! clap! Clap!
Waleed Rishmawi
April 7, 2020 at 5:13 pm
Yogesh: I thank you. have a blessed day
Parasuraman S
April 6, 2020 at 5:07 pm
When I read the heading of the article itself, I guessed it could only be from you, the exclusive expert in 'welding' the welding machines! Good probing job there with professional work, though the customer did not heed to your good advice! Many thanks for sharing!
Waleed Rishmawi
April 7, 2020 at 5:15 pm
Parasuraman: I thank you my friend. you are such an encouragement to me. I offered him a free replacement yet he would not take it. oh well, life goes on. have a blessed day
Albert van Bemmelen
April 6, 2020 at 10:39 pm
Although this was a regular customer who refused your offer to install an even higher amp rated switch free of charge, he had no reason to protest whatsoever!
And I would ban such bad customers for your and his sake. Such devices with questionable repairs easily could cause a whole building fire in the end! Someone already had tampered with its safety!
Andrew F. Ali
April 7, 2020 at 12:11 am
Nice job.
Waleed Rishmawi
April 7, 2020 at 5:19 pm
Andrew: thanks man.. have a blessed day
Hassan
April 7, 2020 at 1:26 am
Yes your good in electronic repair thank you for your articles
Waleed Rishmawi
April 7, 2020 at 5:20 pm
Hassan: you are most welcome and I thank you for liking my articles. have a blessed day
Waleed Rishmawi
April 7, 2020 at 5:19 pm
Albert: Totally agree my friend but she he refused, I can not do anything about it except to give advice and no more than that. I get many machines with disconnected power switch and I always offer to replace or reconnect it for free some listen and other do not care as long the machine works. have a blessed day
Gassan Ali
April 9, 2020 at 2:55 am
It's great to read an article from the master of welding machine repair during these hard times. I'm learning a lot from you.
Waleed Rishmawi
April 9, 2020 at 3:44 pm
Gassan: thanks. I am very glad to hear that. Have a blessed day and be safe
Kyle
November 3, 2020 at 2:51 pm
I have a selco genesis1500 inverter welde,with tig and stick welding switch. Wen on stick welding,the green small leds flash on mother board,and it only makes a small spark on the electrode,but no welding wat so ever. Pls help