Nokia 8910i mic and slider problem

[GuiltyGear]

Hi everybody.

I have received a Nokia 8910i from a friend which seems to have a few problems.

1) The slider doesn't go very smooth. Sometimes it does, sometimes not. It seems to hang when it's 2/3 open and I need to open it manually. Could this be a string issue?

2) When on a call, the other part say they hear me very low. Tried it with different people and the same problem. They can hear me normally only when I put my ***** very near the mic. Should the mic be changed or what do you think may be the issue?

Everything else works fine. I can hear others very well, the buzzer works good, the keys, screen and everything else. Hope anyone has any idea, because I would really love to use this wonderful phone. And by the way, I have good experience with electronics (not specifically phones) and it won't be a problem disassembling and fixing any simple hardware issues.