Hello Praveen,
Try the following solutions;
# Check the Lcd and motherboard connector. If the connectors are somewhat black, the problem may be caused by the connectors being damaged.
# Assemble the phone EXCEPT for the steel side panels, the screws and the back cover. Turn the phone on and see if the problem has been solved. If so, then refer to my post in the LG V10 section.
# Replace the motherboard and see if the problem disappears.
Best of luck.