Reply to Broken Down A&H Xone 4D - repairable?

I recently bought a 2nd hand Xone 4D, absolutely loved it.
Last friday, I was just playing with it at home when, after 2 hours of playing, I heard a small bang (like the sound when you turn on your mixer and your monitors are already on, but a bit louder) and it smelled a bit burnt.
It was completely dead after that.

Now, I don't have the original invoice, but I doubt it's younger than 1 year... Is there any way I can check this? By serial nr. or sumet?
If it's out of warranty, what could have gone wrong, is it repairable?

Since it's not really a cheap piece of kit and I only had it for little over a week, I really hope this can be fixed or replaced..
Any suggestion or help is much appreciated.

Regards