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Dry Solder Caused Foxin Computer SMPS To Go Dead

By on October 21, 2020
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MODEL AND MAKE: Foxin FPS 500C ATX Power supply of Computer


atx power supply repair

TROUBLE SHOOTING AND RECTIFICATION DONE: As the IT maintenance guy at the hospital had already done the preliminary cleaning, it saved my work. I removed the board, did some fine cleaning. Observed a lot of dry solder on the board. Checked for any bulgy caps or strained components. Could not find any. ESR checking of all caps was well within the limits. Ring testing of the SMPS showed healthy too. So I did retouch of all the points on the board, cleaned it up thoroughly using IPA and looked for any man-made shorts. As everything looked very positive, shorted the green and black at the socket, connected the Fan and applied power.

I was glad to see the fan running but with noise and jerks. So removed the fan, cleaned it thoroughly, opened the cap and applied a couple of drops of oil and closed the sticker cap. Then when I retried, it was very smooth and no noise too! Connected my Power Supply Tester and got a full certifying result! Mission accomplished without any complications, but satisfaction never hesitated to jump into its collection bag!


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fixing atx power supply

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This article was prepared for you by Parasuraman Subramanian from India. He is 70 years old and has more than 30 years’ experience in handling antique equipment like Valve Radio, Amps, Reel Tape Recorders and currently studying latest tech-classes conducted by Kerala State Electronics Technicians’ Association. He has done graduation in BBA degree, private diploma in Radio Engineering and retired as MD of a USA company. Presently working as Consultant to Hospital and other institutions.

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  1. Albert van Bemmelen

    October 21, 2020 at 7:29 pm

    If all SMPS repairs were so easy the successrate fixing my bad units would be much better! Even 2 brandnew identical 450Watt units a friend of mine bought were both destroyed right after the other within a few seconds after switching on and couldn't be saved because of unknown IC parts.

    • Parasuraman S

      October 21, 2020 at 9:56 pm

      Yes. The ICs are either not available or no datasheet can be found in the web search! Nevertheless, I like to take up SMPS work as much as possible, because of Jestine Yong's encouragement in his book.

  2. Waleed Rishmawi

    October 22, 2020 at 4:29 pm

    cold soldering joint happens a lot in this kind of power supply. If I open a power supply like that first thing I check is bulged capacitors and dry joints, if nothing is found I just give it back to the customer unfixed.
    good job on the repair though. have a blessed day

    • Parasuraman S

      October 24, 2020 at 11:23 pm

      But, why give it back unfixed, without identifying the problems! That's strange!

  3. Henrique J. G. Ulbrich

    October 27, 2020 at 1:48 am

    An easy repair. Thanks for sharing. Glad to know you revived your satisfaction bag.

  4. Yogesh Panchal

    October 27, 2020 at 8:28 pm

    Good fix, Sir

  5. Raj

    November 3, 2020 at 4:59 pm

    Great tips.. thanks


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