Why my MH-25 adapter is not working?

It was three days back when I was charging my enel15 battery of d7100 in my 25 charger. Battery was charging properly, suddenly I noticed the orange led is blinking unusually fast. I found it was not charging any more. I followed some articles and some YouTube clippings but none of them could solve my case. I have managed to open up the adapter and found the circuit board and all its components are intact, no smell or sign of burn. Can't understand what to do now. Need urgent help. Thank you in advance..