A Dead Power Supply Repaired And Maintained
My cousin brought this power supply for repair. He said that this power supply is used to power up an electrical stove and suddenly they heard a popping sound and the stove stopped working.
I can see where the popping sound came from and as seen in the photo the board took a lot of damage and hopefully it is repairable.
I took the board off the heat sink to see if there is any damage on the other side of the board and I found this.
I think I can handle this so I started taking the shorted parts off and cleaning the board to see what can be done here.
I took all the shorted/burnt parts off and started to fix the board on the less damaged side.
I connected the broken tracks and headed to the other side of the board.
I replaced the big exploded cap with the exact specs, 47uf/400 volts, the four diodes as well although not all the diodes were shorted and the main fuse.
I checked the board for more damaged parts and found none.
The board looked nice and clean but most important will it work? This is a moment of truth to see the outcome of this repair.
Yes, the board worked like a charm. Of course I connected it first through a current limiter and the light bulb came on for a few seconds and it went dim which is an indication that all is well and ready to be used in a normal power situation.
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 A Simple Fix To A Dead Electronic Scale Brought It Back to Life
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lloyd
November 12, 2023 at 9:47 am
WELL DONE
Parasuraman S
November 12, 2023 at 10:18 am
Another double satisfying service work! You are indeed very lucky to have such services done to your relatives! Almost all my relatives are living very far away! Many thanks for sharing!
Waleed Rishmawi
November 14, 2023 at 1:03 am
Parasraman: indeed my friend. family come first although I do not get paid but it is worth the time and effort. have a blessed day. you are most welcome
Albert van Bemmelen
November 12, 2023 at 5:41 pm
Well done. Odd thing here though is that the original fuse didn't protect the primary circuit when the current got too high, so badly that even the wider copper tracks on the solderside burned open? Why it probably is questionable that the fuse rating is the right one.
Yogesh Panchal
November 13, 2023 at 3:49 pm
Good Job! Waleed
Waleed Rishmawi
November 14, 2023 at 1:15 am
Yogesh: thanks man. have a blessed day
Waleed Rishmawi
November 14, 2023 at 1:14 am
Ablert: thanks man. I asked the same question myself and I checked the original fuse on a same working board and it was 3:15 amp rate. Not really sure what happend here and why the fuse did not protect the board. I did not want to take the rist and replacing it with a 2 amp fuse so I rostored the fuse to its original value and hopped for the best. have a blessed day
mike
November 14, 2023 at 8:11 pm
@Waleed:
You wrote:
"Of course I connected it first through a current limiter and the light bulb came on for a few seconds and it went dim which is an indication that all is well and ready to be used in a normal power situation."
Could you expain how the testing with a bulb works?
Waleed Rishmawi
November 16, 2023 at 4:11 pm
Mike: greetings
when you have a short on board the parts will blow up and get burnet but when replacing the faulty parts with good ones and not sure if the short is gone you connect it to a current limiter so if there is short the light bulb will come on brighlty saving all the new parts you installed but if it went bright then went dim there is not short left on board and it is safe to power the power supply through 220 volts. you can search it online for more information and you can build a cheap ones to help you in your repair. have a blessed day
Albert van Bemmelen
November 14, 2023 at 11:52 pm
I think that the glass fuse was too slow why it didn't protect the primary circuit in time?
Maybe we could measure the exact current that flows at inrush switch on moment, and the current when the stove is at maximum heating to determine the here right needed better protecting fuse?
Waleed Rishmawi
November 16, 2023 at 4:15 pm
albert: in the area where the stove is right now there is a lot of power issues that the company is working on to get fixed but with the war situation is not easy to go and get it checked but your are right the current can be checked but right not it is not the right time to do. thanks for your input and have a blessed day