FWIW I've come across a lot of them, own a few rescued ones myself, and the brushoff, clean, lube and working the pins up and down method -usually- sorts them out electrically
Even if they look ok and functional, I do it anyway, perhaps that's why some of my batteries last ages, even if tired to begin with
Sometimes there's an intermittent hidden short in the cable somewhere, which I assume would assist in a few problems and heat at the connector ends
I usually feel for bumps or soft spots along the
al dente spaghetti grade cable to try track down the 'not so sweet' spot
I'll have to rig up some some sort of interface 'one day' (
) so I can use a multimeter at the end to make the task easier
rather than just using The Force BTW folks, I'm referring to the real deal Apple Magsafe adapter/chargers,
if it's a OHL Apple knockoff I don't bother
and order/recommend an original replacement
If there's a knockoff out there I'm unaware of that's better quality, please don't be shy to comment below