Door will not open on dvd player

Is there a "lock mechanism" that will need to be undone?....accordianman

I had the same problem with a T-600 D. Device is a few years old.
Solved the problem by slapping the **** out of it.
I mean, slap it like it's your wife and you just caught her cheating on you.
Don't worry about breaking it. It's broken anyway.
Slap both sides; first one, then the other, then simultaneously.
Slap the top and slap the bottom.
Then pushed the eject button and now it seems to work.
Oh, if it's under warranty, you might check with the manufacturer to see what recourse they can offer.