Depending on what you may have tried to resolve the underlying issue,
you may have to try several things... or just a few over again. ~ IF you
have a clean 'magsafe port' and 'magsafe plug' with pin springs that
are not stuck, this aspect of routine maintenance could merely be given
a courtesy check (any time you use it) and debris, lint, dust, etc removed.
With devices that use battery and mains power adapters, there are some
items that may need doing to be sure the battery (if it is good, not worn)
is getting a ration of power from the adapter. Because these can charge
OK while not giving the Mac enough power to start; troubleshooting to
see what is involved with your configuration should be a rare happening.
If there's debris in power port, and if you know the battery is less than 14
months old, you may see if resetting System Management Controller helps.
Number of charge 'cycles' and also age of the battery are indicators of wear.
The process, followed correctly, may be all it needs. Hard to say at distance.
• How to reset the System Management Controller (SMC) on your Mac - Apple Support
Read through all of the 'Before you Reset' because these detailed steps may
resolve the issue if you try them in the order indicted within instructions. And
then, you could try the instructions on how to reset SMC - for the portable mac.
There is a secondary 'reset' for other items that may affect your Mac, NVRAM.
• How to reset NVRAM on your Mac - Apple Support
Other understanding of using portable Apple computers with power adapters
and batteries can be found in the following Apple Support reference pages:
- Apple Portables: Troubleshooting MagSafe adapters
- Mac notebooks: Using and maintaining your Apple MagSafe Adapter
- Mac notebooks: Reducing cable strain on your MagSafe power adapter
- Intel-Based Apple notebooks: Identifying the right power adapter and power cord
There also are a few ifixit kinds of online tips pages for those who may wish to
test their mechanical aptitude, one item that may affect the power connection
to the extent of failure; one item to check, after assuring battery and the power
adapter are both good, and inspecting/cleaning the Magnetic port & jack...
Consider having the 'magsafe DC-in Board' replaced. The ifixit site for each
model macbook has a specific instruction for this; but take to an authorized
Apple service provider if you're unable or unfamiliar with repairs of this kind.
In so much as your symptoms require certain troubleshooting steps, try the
steps prior to using the actual 'system management controller reset'.
My MacBook 13-inch (2006) had issue after sitting way too long, and would
only charge up 27% and the light would go green. I chose to follow each of
the 'before you reset' SMC steps, several times, and never did perform the
actual reset. From experience, I'd tried with a different model, to test this out.
So I was able to recover full use of the battery; as far as it could be recovered.
And cleaned the contacts among other bits before calling it all good. But you
may find the unit could need a new battery or other, after troubleshooting...
In any event...
Good luck & happy trails! 🙂