It is completely normal, that new thigns have a certain smell once they are heated.
Take a smell from your router, your TV. Take the smell from your computer exhausts from the PSU.
There is a certain "electronics" smell, that is completely normal.
If the PSU burns up (I destroyed a few with experiments when I was younger) the smell is different, it is more pungent and not as "sweet" from the smell. Also, the smell from destroying the capacitors in PSUs is quite intense.
If you have time to spent, a psu to burn, want to see this smell and won't sue me for whatever happens when you do this, put a psu in 110v mode when on a 220v electrical supply. If your house burns off, don't blame me, but the smell is what you smell when electronics "die."