Smoke and burning smell once powered on!

I had a 2TB TimeCapsule which was working perfectly fine until few years ago. Decided to power it on and check it if it still works. To my horror, smoke started coming from near the power socket and the i could feel something burning. I unplugged it immediately and let it cool for a while. Now i managed to open it and access the 2TB drive on it. Thankfully my data is still in there and I took a backup. I’m afraid to put it back together . Any idea what could have gone wrong? What needs to be fixed?