HP Pavilion x360 13' - constant ticking sound from back

Hi,

Day before yesterday i bought HP 13-A013CL. As soon as I start the the laptop there is constant ticking sound (like spark)  from the back. This sound is over and above processor fan sound.

Please let me know if all the model has this problem and how can i get rid of that sound.

Thanks in advance.

Regards,

P