Hi @ashishkuma41144
Is the audio heard when using headphones connected to the laptop clear and not crackling or is it also noisy ?
If the internal speakers are the problem, go to p.83 of either manual linked below, to view the procedure to remove/replace the speakers.
There are two service manuals for the laptop model.
There's a [https://dl.dell.com/content/manual35801071-latitude-3420-service-manual-for-computers-with-integrated-graphics.pdf?language=en-us|Dell Latitude 3420 with integrated graphics] i.e. 1 x Intel GPU integrated with the CPU and a [https://dl.dell.com/content/manual35345437-latitude-3420-service-manual-for-computers-with-discrete-graphics.pdf?language=en-us|Dell Latitude with discrete graphics] i.e. 2 GPUs, 1 x Intel GPU integrated with the CPU and 1 x Nvidia GPU mounted on the systemboard.
Search online for ''0C402X'' to find speaker suppliers that suit you best.