Chosen Solution
Hello, I have replaced wire of charger magsafe 2 45w. Now measure pins, and pin2 and pin4 gives me 0,8V power. Maybe something is wrong with charger ? Maybe it gives that power because wire from china ? Thanks for any answer Update (09/29/2017) I measure magsafe 1 charger from macbook pro 2012 mid, ant pin2 and pin4 shows me 6,7V and something like that. But magsafe 2 only 0,8V±… How to be sure charger works well ? I don’t want damage macbook air….. Update (09/30/2017) Then i measure charger wire…. charger end metal trim shows me 3V with all pins inside. It is normal ? Its only on magsafe 2. I try measure magsafe 1 on metal trim and pins, shows zero :) By the way, macbook air 2014 have any safety on charging port or etc ? By the way, on magsafe i measure pin 2 and tryed short pin 4 with pin 5, then i got 15V output on pin2 and pin4. So looks like charger works…
The Magafe 2 connector will normally not have voltage output until it receives a signal from the computer to allow power through (the center pin communicates with the macbook for this reason). That is so it will not short out on other metallic items. It is normal to not have voltage until it is plugged in. I have never tried a replacement magsafe cable from china, so good luck!
No, it is wrong to assume something is wrong, comparing its standby potential against a MagSafe 1 power supply. If you did measure before, then you could compare after. That wire from China is not at fault. Standby output of Apple’s MagSafe Power Adapters varies between models.
