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Saving Computer SMPS – PART 7

By on March 2, 2024
how to fix atx smps







Case (1) SuperComp SEP-500 : This SMPS was brought to me in dead condition with fan broken. I saw bulgy capacitors and a lot of dry solder. I replaced all the electrolytic capacitors and retouched the board and replaced the fan, upon which it worked very well with a load of 12V/25W Bulb. Please see following picture; also provided is the readings of the tank capacitors.

tank capacitor

Case (2) Zebronics SMPS – N450W: Same report as above. The value of 470uF showed around 300uF. A lot of dry solders. All electrolytic capacitors were replaced. Board was retouched with fresh solders.

Fan was lubricated. Board was thoroughly cleaned, both top and bottom. When the SMPS was tested with same load like before, it worked superbly well. Tested it for hours before closing the cabinet.

how to fix atx smps

You may click on the above photo to enlarge it

As you will notice, the tank capacitors had higher diameter, though the height was almost half. I had to therefore elevate one cap to accommodate both.

Missions accomplished satisfactorily qualifying for getting entry into the prestigious collection bag. Both belonged to the hospital. Hence no charges were collected for anything!

Lesson: Accept such SMPS works; don’t bother about income much to save E-Waste. Consider it as our Contribution!


This article was prepared for you by Parasuraman Subramanian from India. He is 74 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 article on Three Wire Module Fixed In IMPEX 2.1 Multimedia Speaker System Model Musik Plus




  1. Albert van Bemmelen

    March 2, 2024 at 5:13 pm

    I agree with your lesson to accept such SMPS works to not bother about income too much to save E-Waste, considering it as our Contribution.
    But please do not forget to also watch on your own health and your wealth, since we still can't solve all of earth's problems even if we tried!

    • Parasuraman S

      March 3, 2024 at 11:16 am

      Many thanks for your genuine concern, dear! I take care of it to the best of my ability. In fact, I take a break quite often!

  2. Anwar Yunas Shiekh

    March 2, 2024 at 8:31 pm

    I like things to fit; pity the replacement primary capacitors had to be mounted like that.

    • Parasuraman S

      March 3, 2024 at 3:29 pm

      Yes, sometimes we do not get the correct size! Many thanks for your comments!

  3. Tayo

    March 3, 2024 at 8:14 am

    A well made and well designed power supply should always be saved. Money be d*mned! We are getting to the point where such high quality power supplies are hard to find or are very very expensive. A good power supply will often outlast the device its powering. Well done Maestro!

    • Parasuraman S

      March 3, 2024 at 3:29 pm

      Yes, fully agree with you! Many thanks for your wonderful comments!

  4. Waleed Rishmawi

    March 4, 2024 at 2:50 pm

    these power supplies in my country are very cheap and I always do not accept them in for repair because the customer could buy them for less than 10 USA dollrs. any way, good repair and thanks for sharing. have a blessed day

    • Parasuraman S

      March 4, 2024 at 10:24 pm

      Yes, you are right. It is available cheap here also. But my free repair is a service to the hospital, which I very much enjoy and feel proud to do!

      • Waleed Rishmawi

        March 6, 2024 at 1:07 am

        I did not know that. Keep up the good work

        • Parasuraman S

          March 8, 2024 at 8:01 am

          Thanks, dear!

  5. Yogesh Panchal

    March 5, 2024 at 6:06 pm

    Good Job! Sir,

    • Parasuraman S

      March 8, 2024 at 8:00 am

      Many thanks, dear!

  6. Tito Kanshulu

    March 7, 2024 at 2:42 pm

    Good job Sir. I like the way you articulate these electronic issues

    • Parasuraman S

      March 8, 2024 at 8:05 am

      Many thanks, dear! The communication skill was obtained from stenography that I learned after matriculation and that was the main reason why and how I could grow up in my career and reach a level, which I never dreamnt of! The diploma in Radio Electronics helped me to grow my interest in electronics and reach this level, an added graduation which I did while working in BPL helped me further too!

  7. craig

    March 8, 2024 at 1:32 am

    You all have such excellent skills and repair articles and I like your trying to keep stuff from the land fill.
    I am just an avid electronics hobbyist have been since high school 1970
    Just got me an esr meter for my bench and boy howdy does it tell the truth about a capacitor but my question is what would be an "ok" reading for a cap ESR value wise, Max value oh...lets say 1000 MFD and below. I don't use any cap with an esr of 1 Ohm or more except for the big super caps which can get to 100 ohms esr...10-50k MFD...what say you

    • Parasuraman S

      March 10, 2024 at 5:49 pm

      Many thanks for your comments! Here is the link which provides details of ESR values capacitance-voltage-wise:

      You can also see
      (The ESR value graph is on top of the instrument itself)

      Hope this helps!


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