Buzzing sound from speaker of 3310

Hi all,
really need some help in solving this problem, i have a 3310 that the speaker give out a buzzing sound everytime it log on the the network or making a call out.

the sound is like when you bring you handphone close to a radio speaker when you try to make a call.

i have try changing speakers but it not work, i try reheating on the N100 ic chip also did not work. i thought that it was a short so i clean the borad 2 time but it did not help also.

guys running out of idea on what to test, please help :(

thkz

somethimes rehot dosent help, that means the ic is already demage so you can rehot 100 times and you still have the same problem.
Change COBBA... i already fix 20 fones with this problem.

Regards.