I've got an Acer Aspire 1642WLMi, and when i plug the charger in, the screen blinks brighter and the darker continually as the charger is only working for a seond then stopping. If i move the wire around it sometimes works for longer but will then get bak to it's old habits.
The fact that moving the wire around helps likely means you need a new power cord. And if that is not the case you probably need a new battery (they do die after a while)
It sounds as though the cable has either broken inside the insulation, or you have a dry or broken soldered joint where the cable connects to the PSU PCB
As a rule charger cables or infact most cables don't like to wrapped around the charger as is in time wrapping and un wrapping them eventually causes the copper conductors to break under the insulation.
I had a similar problem with my Dell Inspiron after 4 years, it turned out to be the power cord was broken inside the cabling. I recommend trying a new power cable before anything else.
check if the batery holds charge, if it does it, maybe your battery cell is right, and you only have to buy a new charger, I'm sorry, but I guess, in these kind of situations, no one will give you good news, you certainly will have to purchase something.