From Repair Mobile

Rw6818 Sound suddently mute

I believe you are not able to hear the audio/sound with the speaker output of your iPAQ.

Joey, this issue generally occurs if the audio out port becomes faulty. It could be the due to the head set audio jack that may be slightly bigger in size, which can be the cause of the issue. It clearly seems to be a hardware issue. However, I would suggest you to perform the following workaround in order to resolve the issue. More details [1] - thanks to hp.com