A Shorted Board In A Power Supplied Repaired
An electrician brought this big power supply for repair and seems like he checked with the manufacture about the usual fault in such device so he brought only the main power board of the power supply.
Checking the top side of the board I could see a fuse missing and I when checking with the naked eyes I could see nothing burnt or exploded so took the screws off and checked the other side of the board.
As I was informed by the customer that the main fault usually happens in the lower side of the board attached to the main heat sink and that is the main disaster because they head a big bang coming from the device.
The main reason with this mess is that the electrician tried to do something to the main input of the device without disconnecting it from the main power source which ends up in this messy fault. Let us check it out.
I could see and understand what the electrician was talking about because that is a big mess.
I need to clean the area before finding out which is shorted and which is not but eventually all these parts has to be replaced if they want the job to be done professionally.
The cleaning was done and I found only one shorted part so I talked to the customer and suggested that the four parts should be replaced and right away he agreed to my suggestion. The part number is: 57N65M5; 650 volts, 42 amps N channel Mosfet.
Click on the above link to access the STB57N65M5 Datasheet
I do not have this kind of Mosfet available in the shop so I informed the customer and he was willing to order them online; two weeks later the customer called me and said that he has the parts but when he brought them to my shop it was not the same size but same part number so he had to order them again and return the old ones back.
After one month of waiting for these Mosfets, finally they came and I was able to install them back. I cleaned the area, put back the yellow insolating piece that comes beneath every Mosfet, added thermal past and called the customer for pick up.
I do not know if the power supply worked or not because the customer did not updated me on that but I did what is needed to be done and to that I could say
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 article on An Alarm System Board Repaired and Maintained
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11 Comments
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Isaac
June 1, 2024 at 2:01 pm
This is wonderful
Waleed Rishmawi
June 1, 2024 at 3:47 pm
Isaac: thanks man. have a blessed day
Parasuraman S
June 1, 2024 at 2:04 pm
It is sad that the customer did not give you feedback. Anyhow, you have done your part well!
Waleed Rishmawi
June 1, 2024 at 3:52 pm
Parasuraman: by the time the article was written he did not respond but after that he called and said there was still something wrong with it. it did not explode this time but he needed to talk with the manufactur and they told him to replace one of the tiny boards there and then it worked fine. it seems like the main board was effected with the short and it has to be programmed to work again. have a blessed day
Yogesh Panchal
June 1, 2024 at 2:59 pm
Good fix, Waleed
also it is good idea to ask customer,to order the parts in critical repairs.
so that they also come to know why repair delay is happen.
Waleed Rishmawi
June 3, 2024 at 1:56 pm
Yogesh: thanks man.
this guy understands the hassel we go through at technician to order and wait for parts but I appreciate your comment, in gerneral you are right. have a blessed day
Albert van Bemmelen
June 1, 2024 at 5:22 pm
The replacement was professionally done like always. And replacing mosfets is your specialty of course! The top side of this board at least looked very decently made because they only used quality ic sockets!
Waleed Rishmawi
June 3, 2024 at 1:58 pm
Albert: I really appreciate the postive encouragement. yes the device over all is well built and nicely designed to preform well and last long but the electrician did a mistake here trying to do something with it. have a blessed day
Philip
June 3, 2024 at 7:52 pm
The article title says "repaired shorted board". with all due respect our seniors what was repaired ? Then no bulb or multimeter was used to test for a short presence ? Proof of repair ?
Waleed Rishmawi
June 4, 2024 at 11:14 pm
Philip: yes shorted board was brought to my shop and I was as asked to replace the shorted parts on it. Why test with a multi meter and I already seen the shorted parts and were replaced with brand new ones? Why use a bulb when I have only one board and not the whole device? The customer took the board and installed it but did not update me on the situation. I did what the customer told me to do and based on that my job is done. Have a blessed day
Tito Kanshulu
June 8, 2024 at 1:14 pm
Good fix Waleed. Thanks for the eye opening repair story