Chosen Solution

can talk, and hear with and without earphones. can hear, not be heard with speaker on. cannot hear music. i have replace a brandnew loudspeaker ( by the charger port ). didnt solve the issue, please help, thank you.

could be either 2 things,

  1. you upper mic and dock connector need te be replaced upper mic is connected to the power button iPhone 4 Power & Sensor Cable Replacement dock connector is responsible for the speaker power iPhone 4 Dock Connector Replacement
  2. your audio ic has failed and you can try the temporary fix ali suggested above or take it to a professional repair shop

The issue you are having is due to a motherboard issue a fix can be found here http://www.youtube.com/watch?v=0jhWxYTVx… Regards Ali