Possible to measure the output voltage of magsafe2 with a multimeter?

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Level 1

12 points

Possible to measure the output voltage of magsafe2 with a multimeter?

As per subject, I have what i suspect to be a faulty 85w Magsafe 2 adaptor for my MBP Retina and I would like to determine if it is truly the adaptor that is faulty, or weather there is a fault with the MBP itself.

Long story short, the MBP is no longer charging and the LED on the Magsafe 2 connector is no longer coming on, yet was a couple days ago. I know the obvious answer is that if the MBP is not charging, the adaptor is faulty. However would the LED come on if for instance, there was damage tio the logic board etc...?

Although nothing has recently happened to either the MBP or adaptor, it did suffer a fall 18 months ago which resulted in a repair via an authroised repairer, although i am not entirely confident with the repairer but was forced to use them by my insurance company. Admittedly the MBP has worked flawlessly since that repair (aside from a couple of dead pixels but thats another issue) but i cant help but worry that something else is amiss.

MacBook Pro (Retina, Mid 2012), OS X Mountain Lion

Posted on May 20, 2014 12:52 PM

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Answer 1

Soupladel Author

Level 1

12 points

May 20, 2014 1:25 PM in response to OGELTHORPE

I am aware of the pin layout of the connector but i had read that it will not output anything until activated to do so via the control pin (centre) and am unsure if it is possible to safely trigger this in order to get a reading.

I might have tried the suggestion of checking the system information if the MBP was not now dead, but even so, it would not definatively tell me if the fault was in the adaptor or the logic board surely? I mean if it said "connected: no" all that would tell me is that it is not detecting the connection rather than the connection not being there and i am unclear on how the MBP detects this (other than the obvious i am getting power/i am not getting power).

I dont mean to dismiss your help, but coming from an electrical engineering background my instinct is to determine if there is juice coming out of the adaptopr and if not i can take the whole thing in for reapir rather than wait for apple to send me a replacement magsafe adaptor which may or may not solve my problem.

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