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Replacement Of Two Bulged Capacitors And Dry Solder Patch Up Brought Life Back To SMPS!

By on April 1, 2021
atx power supply fix






how to fix atx

This SMPS was brought to me with the complaint that it was dead. After opening and cleaning up the inside thoroughly, when I did a visual examination, I saw two capacitors were bulged. I also saw a lot of dry solders on the board. One connection was not making any contact at all!

how to fix atx power supply

After replacing the two bulged capacitors, I did a thorough retouching of all the solder joints. Then cleaned up the board thoroughly using IPA. Then when I tested the SMPS by shorting the green pin to ground, it was found working very well. The voltages were also checked to be sure.

There are two ICs for voltage control in this SMPS. One is LM339 and another is KA7500B. Here are a few more pictures to conclude this short article, without forgetting to add satisfaction to its collection bag:

how to fix and repair atx power supply


This article was prepared for you by Parasuraman Subramanian from India. He is 72 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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You may check on his previous repair article below:




  1. Albert van Bemmelen

    April 1, 2021 at 5:10 pm

    Another well carried out job Parasuraman. Why you whould doubt replacing both rusted resistors I however do not know. The SMPS tester you used, I also have this same model, probably will fail in case testing a high power desktop unit wrongly is tested good on the weak internal load of this tester.

    • Parasuraman S

      April 1, 2021 at 6:55 pm

      Many thanks for your comments!

  2. Humberto

    April 1, 2021 at 11:38 pm

    You have done a great repair: first a cleaning and finally the reparation. That SMPS can be used by a long time without any kind of preocupation. By the way, do you lubricate the fan(s) too?

    • Parasuraman Subramanian

      April 2, 2021 at 11:53 pm

      Yes, I do lubricate the fans. Many thanks!

  3. Andy Shiekh

    April 2, 2021 at 2:27 am

    Do people here have a favorite low ESR capacitor brand/series?

    • Parasuraman Subramanian

      April 2, 2021 at 11:54 pm

      Couldn't catch your point!

  4. Anwar Y Shiekh

    April 2, 2021 at 7:02 am

    I am pretty sure I have read an article where he oils the fans

    • Parasuraman Subramanian

      April 2, 2021 at 11:54 pm

      Many thanks!

  5. Yogesh Panchal

    April 2, 2021 at 3:10 pm

    Good Job! Sir,

    • Parasuraman Subramanian

      April 2, 2021 at 11:55 pm

      Many thanks!

  6. Waleed Rishmawi

    April 2, 2021 at 4:29 pm

    well done on the repair. about the power supply tester, I have the same exact thing but I never had the chance to test it out since in do not repair computer power supplies. is it any good? have a blessed day

    • Parasuraman Subramanian

      April 2, 2021 at 11:56 pm

      It's a good tool! It saves us time! Many thanks!


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