Can't charge my Acer Aspire 5534

ok i'm a really newbie when it comes to laptops. i have an acer aspire 5534. it has been 4 months on me and i have it's battery replaced due to its defect - i can't charge my laptop. whenever i plug it, the orange light just blinks and it doesn't charge.

now, i got the same problem again. but there, i was able to charge it successfully and i was surprised.

i was just confused because maybe once i will charge it again, the orange light will come blinking and i don't want that of course.

we even brought this on the repair center twice. 1st was the battery was replaced, and now the second one, they want it's mainboard to be replaced. that's why we chose to just let it be that way. the laptop never got repaired but now, i was able to charge it. lol.

is it the wiring? oh btw, the service center guy said that they also replaced the hole where i should plug in the charger for my laptop (sorry i don't know how the call that one).

i am really confused and of course, if there's a way to repair it on my own, i want know.

thank you so much!