Greetings Ravi,
My NX5 had to be serviced about 2 years after purchased. Had the same symptoms as yours. Sony said it was damage to the mother board caused by me placing / forcing the memory card in upside down. Total BS! They had me by the bells. Being a Sony ex-employee in Culver City got me a discount on a very expensive repair. Really wanted to argue with him but like I said, the grip was tight. So far, camera has been good with no issues for $1300.00. This is definitely a Sony issue and it’s really sad that they treat loyal customers in this fashion. Do really like the camera btw. You will let me know when the lambs stop screaming