Whatever the cause may be in most cases it s actually the adapter and not the magsafe connector.
Mac magsafe power adapter not charging.
Then reconnect the charging plug to the wall outlet then reconnect magsafe to the macbook pro.
If the 2012 macbook pro is the model without the retina display with the cd dvd drive then the 60w would work on both.
Let it sit unplugged from anything for about 5 minutes.
The adapter only charges the computer intermittently.
But it should power and charge your mac like the adapter that originally came with your computer.
Your power adapter won t charge the computer.
It could be frayed broken or burned.
Maybe the adapter is not getting its power could be a loose socket or an improper connection.
If you need help using your magsafe adapter see apple portables.
Disconnect the magsafe adapter from the mac and from the power outlet.
The adapter s white insulation separates from the magnetic end of the magsafe connector.
A simple way to see if it s the problem is by doing a thorough inspection of the entire cable.
A replacement adapter might not be the same size color shape or wattage as the original adapter that came with your computer.
If connecting a magsafe adapter to a macbook doesn t light up the power led chances are the socket you are connecting to is not working okay.
Inspect every inch of the cable.