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Two AC Adapters Were Saved From Dump

By on August 5, 2022
Two AC Adapters Were Saved From Dump

 

 

 

 

 

 

 

These two AC Adaptors of the hospital, where I work, were brought to me in dead condition.

  1. DELTA ELEC EADP-60BB A : When I checked this adaptor for output, it was coming and going dead. On checking the primary with Ring Tester, it did not show any unhealthy symptoms. On further checking I traced that the fault was on the LED of power on indication. It was dead short and the resistor was burnt. I replaced both and it worked perfectly well when checked with a 12V, 25W Bulb as load. As the soldering was fine, I did not retouch the board. The capacitors also passed ESR tests.

esr test pass

  1. AC ADAPTOR LR 120500 : When I opened the cover, I saw two bulged capacitors in the secondary, which could only be the cause for failure.

bulged cap in smps

After replacing the caps, when I checked, the adaptor was working.

As the board looked very neat with no dry solders, I checked the remaining caps with ESR meter and it passed the tests.

fixing smps

I gave a 12V, 25W automobile bulb as load and checked and it was found working perfectly well.

testing power adapter

Here is a picture of the caps replaced:

cap replaced in smps

Satisfaction in double found its way into the collection bag!

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 article on No Load Taking Computer SMPS Restored

 

Likes(58)Dislikes(0)

20 Comments

  1. Albert van Bemmelen

    August 5, 2022 at 10:06 pm

    You like usual have the capacity to replace all capacitors when needed.

    Likes(3)Dislikes(0)
    • Parasuraman S

      August 6, 2022 at 9:24 am

      Many thanks for your comments!

      Likes(0)Dislikes(0)
  2. Imran

    August 6, 2022 at 5:36 am

    Shows nothing goes to waste.. Good job

    Likes(1)Dislikes(0)
    • Parasuraman S

      August 6, 2022 at 9:24 am

      Many thanks for your comments! Yes, we are like goal keepers, in a sense!

      Likes(0)Dislikes(0)
  3. Waleed Rishmawi

    August 6, 2022 at 2:58 pm

    got to love the easy repair sometimes. thanks for sharing and have a blessed day.

    Likes(1)Dislikes(0)
    • Parasuraman S

      August 7, 2022 at 11:18 am

      Many thanks for your comments!

      Likes(0)Dislikes(0)
  4. Yogesh Panchal

    August 6, 2022 at 6:34 pm

    Good Job! Sir,

    Likes(1)Dislikes(0)
    • Parasuraman S

      August 7, 2022 at 11:19 am

      Many thanks!

      Likes(0)Dislikes(0)
  5. GIFT ELIJAH

    August 6, 2022 at 7:52 pm

    Thanks very much sir, that was a very clear explanation of what you did to revive those two power packs.
    But my concern is that, is it possible for the power indicator to prevent the power pack from working?

    Likes(1)Dislikes(0)
    • Parasuraman S

      August 7, 2022 at 11:20 am

      Yes, if it shorts, the secondary will draw more current and it will be sensed by the feedback circuit to shut off oscillation.

      Likes(0)Dislikes(0)
  6. Michael Gallegos

    August 7, 2022 at 7:26 am

    Whenever I work on these AC/DC power packs I usually find the hardest part is opening them to look at the electronics. Did you you have to do anything special to open them?
    The power ON indicator really surprised me as being the problem. Good job!

    Likes(1)Dislikes(0)
    • Parasuraman S

      August 7, 2022 at 11:21 am

      We may have to pry open many ACAs as these are fixed with glue. Some of these are having screws, hidden underneath the rubber bushes or the label. We may have to press the label gently without causing a tear and see whether there is a screw hole.

      Likes(1)Dislikes(0)
      • Yogesh Panchal

        August 8, 2022 at 2:37 pm

        above comment is Just additional tip to Michael Gallegos.

        Likes(1)Dislikes(0)
        • Parasuraman S

          August 10, 2022 at 8:38 pm

          Good tips!

          Likes(0)Dislikes(0)
    • Yogesh Panchal

      August 8, 2022 at 2:33 pm

      Perfect options guided by Parasuraman sir, In addition if Power adapter is glued
      like Laptop Power adapters just use Petrol / Gasoline using needle Syringe(Used In Medical) and apply it on the edge of adapter joint line. Repeat again after 2-3 minute & after say 5 minutes open the lid of adapter just normally pry it using screw driver it will open easily.No hammering required.

      Likes(2)Dislikes(0)
      • Parasuraman S

        August 10, 2022 at 5:43 am

        Yes, it is a good suggestion. But be careful, if you are near hot items like Soldering Iron etc. There is a chance of catching fire and unfortunately, you can't even see the flame to notice it!

        Likes(0)Dislikes(0)
  7. GIFT ELIJAH

    August 8, 2022 at 9:41 am

    Sir, Your experience is really helping me. Thanks for the further explanation. I am happy with this progressive leaning process.

    Likes(1)Dislikes(0)
    • Parasuraman S

      August 8, 2022 at 6:24 pm

      Many thanks for your comments!

      Likes(0)Dislikes(0)
  8. Wong Sieh King

    August 9, 2022 at 3:33 pm

    It is really a pleasure to read your repair article and I had learn a lot from you ! By the way you had mentioned a website where you can get free service manual for electronic equipment in one of your repair article but unfortunately I couldn't remember the website. Do you mind to give me the website again ? Thank you !

    Likes(1)Dislikes(0)
    • Parasuraman S

      August 10, 2022 at 5:41 am

      Type in make and model number followed by Service Manual in Google Search. Then look for free downloads. That is all!

      Likes(0)Dislikes(0)

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