Magsafe charger/board issues

Here's the situation:

My charger does not work on my macbook unless i push it in, and keep it pushed in; however it works flawlessly on my friend's macbook.

Also, my friend's charger works flawlessly on my macbook.

Any ideas?

Thanks!

You might try a new magsafe charger as that is the easiest to do, but I really have no idea which is causing the problem, the magsafe charger or the input power board? Replacing both can be expensive.

Regards.