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Heres a full solution that may help fix and repair Nokia X3 Headset Problem. This solution shows the entire connection of the Headset Jack line paths such as the headset earpiece speaker and headset microphone or mouthpiece.

If encountered having trouble with headset enhancement such as no earpiece sound or microphone audio signal can be heard on the device. You may first ensure that the headset being plug-in is still working, then proceed to check the headset jack assembly and see to it the it is cleaned and the pins is not misaligned.

Refer the solution below for where to start check or particular spots in troubleshooting Nokia X3 headset enhancement problem on Nokia X3 PCB board.
The headset circuit on Nokia X3 PCB board used an EMI filtering chip in both mouthpiece and earpiece audio signals. The solution below also showed how to mend an alternative jumper solution if having trouble finding a new replacement spare of this said  components.


If having trouble with the  mic and earpiece  chips you can apply a temporary jumper solution below, this jumper solution may also works even if the said chips is not installed. But, this method is not highly recommended for this filter chips serves as a protection for electrostatic discharge and electromagnetic interference.