my mag safe 2 not working I have Mac book pro 15 inch 2015 mid El Capitan OS with a Mag safe 2 85 W but i still not working no light no charging the problem I'm from morocco and there is no apple center and nearest seller is 1500 km away  so i try to fix it myself the pin intput is 230 V but when i check the connector i found 3 V i think it should be between 16-18 V , also the adapter make noise since it failed its like "tak tuk tuk" ....
I already tried:
rest SMC :shift ctrl option power for 10 second
I check electronic lines and all is Ok .
Sorry for my language .
I came across an apple forum when googling your problem in which a person had a same problem:


  Eric's right, these adapters do get a bit hot and can make some sound, yet that sounds much too hot for safety. An AppleCare man told me last month that they were concerned to "capture" adapters that were getting too hot, and promptly sent me a new one in a box in which I was to put the problem adapter and return to them (all paid by Apple of course.)
  My concern then was mostly with the strange sounds it was making, seeming to exactly mirror the CPU whine and activity sounds from my Macbook. Since the new one also did this, when I mentioned this at an Apple Store I was visiting the Genius offered to give me another new replacement. This one seemed silent at first, though on closer inspection in the quiet of home I found the mirroring effect was still present in the third adaptor, though a bit softer. As it happened I've ended up with a replacement Macbook because of another issue, making it four adaptors in my experience. All of them have gotten warm, and a bit hot sometimes, and all have produced the same subtle sounds of the CPU activity. I believe these sound effects result somehow as a result of the magnetic power cord connection, which sits very near the CPU. Unfortunately both my Macbooks have had the CPU whine (a high-pitched buzz) and this then gets reproduced by the adaptors.
  So, I'd also recommend you call Apple or take it to an Apple Store for a replacement adaptor, which should not get as hot as you describe, but may indeed make some strange-seeming sounds.


Hope this helps.