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14.5 volt 3 Amp Apple Power Adapter Repair

By on April 23, 2020
Apple 45 Watt Magsafe 2 Power Adapter Repair - 14.5 Volt 3 Amp

Apple 45 Watt Magsafe 2 Power Adapter Repair – 14.5 Volt 3 Amp

During this Corona Lockdown period it becomes very painful if any equipment fails as you cannot get its replacement or get it repaired.

Same thing happened with one of my colleague. His Apple Magsafe 2 power adapter failed and he could not get any support from anywhere.  Since he lives just in the next building and he knows that I do sometime repair work for my own personal equipment’s, he requested me to look into his power adapter.

apple power adapter configuration

I assured him that I will do the repair for him but it may take some time as spare parts may be the issue. After he left I took the adapter to my work bench and checked the power on adapter cable connector.  The connector pinout is given above. On check I found that voltage is fluctuating between 8 to 11 Volts.

Now I was sure that problem is in the adapter only not in the cable or connector. Since I was opening Apple adapter first time, it took some time for me to understand, how to open it. After dismantling the adapter removed the shielding plate.

Checked the voltage at output point, it was fluctuating. Removed and checked the Rectifier Diode MBR 20100 and filter capacitors. All were OK. I checked all the other SMD components of output section with Multi meter and Component tester. All were fine and readings were within limit. I checked the feedback section of Primary Section by checking voltages on pin no. 3 and 4 of photocoupler EL357N. These were also fluctuating.

apple power adapter repair

 apple power adapter repair and fix

schottky diode for apple adapter

To further confirm whether the problem is with primary section or output section, I used supplementation method by using another 12 Volt 3 Amps adapter. I connected the primary section of the Apple adapter to the secondary section of the 12 Volt 3 Amp Adapter using the 817 C photocoupler. I also replaced the 22 mf 50 Volt capacitor.

When I checked the output voltage it was stable and 14.5 volts. I realized that the problem was with the Photo coupler EL357N. Replaced the 817C and also to be at the safe side I replaced all the electrolyte capacitor of output section.

After this I checked the output voltage it was stable 14.5 Volts. Connected back the cable and assembled back the adapter and checked the voltage at connector. It was stable and with in limit.

power adapter how to apple

Mission accomplished. Thanks & Regards


The author is a Telecom engineer and electronic enthusiast with more than 35 years of experience in Telecom / Broadcasting industry. He is residing in Delhi, India.

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  1. Aziz ola Hassani

    April 23, 2020 at 12:16 pm

    Hi. My name Aziz. Thank you for your email.

  2. Albert van Bemmelen

    April 23, 2020 at 12:54 pm

    Very detailed and useful repair, thanks for sharing! Your neigbour and colleague was very lucky that you were able to help him in these lockdown days! Only wondered what difficulty you exactly had to solve in opening this particular Apple adapter. \
    Since Apple changed the way in how the LCD screens are connected to its pro Notebook monitor shells, from magnets to gluing them together, it now has become close to impossible to open the computer without damaging the glass screens first. And since they cost easily 400 dollar/euro or more to replace them, it now is a great risk to fix any Apple computer problem.

  3. Albert van Bemmelen

    April 23, 2020 at 1:01 pm

    PS: I was referring to the big Apple Pro monitor screens with 20+ inches not the portable ones. But I read somewhere that Apple quits with producing their own monitors now?

  4. Lee

    April 23, 2020 at 2:27 pm

    Nicely done.
    Why are these feedback opto-couplers are failing at all?
    Is it because a high output voltage failure or overcurrent?

    • Lawrence Pina

      April 23, 2020 at 6:20 pm

      Optocoupler failure in certain Apple power supplies has been a commonly observed problem for decades. It's the trademark failure of an OEM they use.

  5. Parasuraman S

    April 23, 2020 at 3:24 pm

    A good professional fix. Many thanks for sharing! (I do not find your name mentioned anywhere!)

  6. Yogesh Panchal

    April 23, 2020 at 5:35 pm

    Good Repair! sir
    welcome to blog.

  7. Hector

    April 23, 2020 at 9:26 pm

    Is there a way to check the Optocouplers?

    • Albert van Bemmelen

      April 24, 2020 at 11:12 pm

      Yes there is, and it is mentioned in several posts in recent articles on Jestine's Blog on how to make such a tester. You also can buy a universal digital tester that test these and much more chips/IC's but they are not cheap. See these links here:

  8. desh raj

    April 24, 2020 at 2:59 am

    awesome explanation sir. thanx alot

  9. nkokana

    April 24, 2020 at 1:19 pm

    well said Mr telecom ..this has helped me a lot as in the field of electronics we are in a state of failer. I have a sansui crt tv that uses the TDA1676 ic on the primary of the power supply.the problem is there is no power on the secondary side of the power supply, which means no out put voltage.there is no voltage to the photcoupler. which I do not know as this type of tv is my first time torepair.can any one help with this.i changed the coupler thinking it might be shorted but no difference

  10. Emmanuel

    April 24, 2020 at 7:03 pm

    Thanks sir, I enjoyed the lesson.

  11. Humberto

    April 26, 2020 at 8:10 am

    Apple devices are unique. Thanks for the article.

  12. Mihai

    April 26, 2020 at 1:06 pm

    Hello Sir , thank's for sharing your experience with us !


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