Dell Inspiron 17 3721 internal Speakers does not works

Hello. Run the ePSA tests. Look for a ‘Perform Quick Audio Check’ on the bottom right side of the ePSA main menu screen. Check if you can hear the 8 beep tones from the speakers.

If you don't hear the beep tones then contact tech support for a replacement of the speakers.

If you do hear the tones that means that the speakers are working and are connected. In that case there is a known issue in the headphone jack that can prevent audio from being switched to the speakers. Contact tech support for a replacement of the headphone jack.

when I plug in headphone then I am able to hear to voice.

Just to make sure we are both talking about the same thing, you mean that you cannot hear any audio through the speakers, even music files that are on your hard drive?