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ICI PC Power Supply repaired

By on August 11, 2015








The Switch Mode Power Supply (SMPS) of this brand is ICI and model: ICI-350W. It was brought to me and the complaint was it was connected into the AC mains of 220 volts with the rear voltage selector in 115 volts position. Of course it was fully dead.

atx power supply repair

The SMPS was disarmed; a piece of cake, only four screws in the upper cover, and you can see the whole power supply board.


First thing checked was the fuse, and it was opened. But before substitute the fuse the active components in the corresponding circuit were tested on: Diode Bridge, both Oscillator Transistors, and some other small signal Diodes and Transistors from the primary side.

Till here all the components were fine. So the fuse was replaced and when the SMPS was connected into the AC mains, the fuse blown again.

The primary side of the SMPS was re-checked and look what I found.

shorted cap

As you can see in the photo above one of the big filter capacitors (680µF/200 volts) of the primary side was shorted when I tested it with the Digital Multimeter. Since I do not have the spare part, I have used 470uf 200 volt cap as replacement.


The secondary side components were checked also and found another e-cap (1000µF/10 volts) with high ESR value. It was tested with my Blue ESR meter.

blue esr meter

It was substituted with a similar cap value. I then powered On the power supply and checked on the voltage readings.

atx power supply voltage

All the voltage values were fine, so the SMPS was fully assembled and put into the PC cabinet. When the PC was turned on, it really worked fine.


Note: the rear voltage selector was put into 230 volts position, because this PC was going to work in 220 volts.

If you want to know more about SMPS repair you can check out this link.












This article was prepared for you by Humberto Rodriguez, one of our ‘Master Authors’ from Cuba.

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Note: You may check his previous repair article in the below link:




  1. Albert

    August 11, 2015 at 4:54 pm

    Another SMPS repair, nice going Humberto! Thanks for Sharing.

    • humberto

      August 12, 2015 at 6:23 am

      thanks Albert

  2. Robert Calk

    August 11, 2015 at 11:39 pm

    Good job, Humberto.

    • Humberto

      August 13, 2015 at 1:30 am

      Thanks Robert, I never thought a big filter could be shorted for selecting bad the voltage-IN

  3. Henrique Jorge Guimarães Ulbrich - Brazil

    August 12, 2015 at 12:08 am

    Thank you for the sharing, Humberto. Once again, I highlight the bad quality of the e-caps nowadays, which did not happen before.

    • Humberto

      August 13, 2015 at 1:32 am

      Yes Henrique, most of the electronic components have bad quality nowadays.

  4. mahmoud

    August 12, 2015 at 5:31 am

    thanks Humberto it is very useful for me.

    • Humberto

      August 13, 2015 at 1:33 am

      Thanks mahmoud. You are welcome.

  5. Gurpreet

    August 12, 2015 at 2:23 pm

    Hello Mr. Rodriguez

    Good job and thanks for sharing this with us.

    Looks good.


    • Humberto

      August 13, 2015 at 1:34 am

      Thanks to you too Gurpreet

  6. Yogesh Panchal

    August 13, 2015 at 12:05 am

    Humberto, Congratulations! for the Fix.

  7. Chris

    August 13, 2015 at 2:25 pm

    Thank you Humberto, I like to read your articles. They are so well explaned and ingormative. Nice resource for all of as who do repairing this kind of electronics.
    Good work and nice job done.

  8. Albert Hoekman, Holland

    August 13, 2015 at 10:59 pm

    Nice job Humberto. It is always hard to find faulty parts in a SMPS, especially in a small one when te parts are mounted very close together and sealed with a lot of silicone sealant.
    Keep publishing your nice articles!

    • Humberto

      August 14, 2015 at 8:31 pm

      Thanks Albert.

  9. mahienn

    February 11, 2016 at 7:00 am

    good job sir

    keep it up

    i thought that all e caps are OK until they are bulged

    can i use 470v 330uf ecap as substitute of 200v 330uf?

    thanx in advance


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