Try this place
There may be some links that will sort out the quest for a manual...
Finding the secret screw! Been there many times...
Usual places
Under labels: use a pencil or soft nosed tool and rub it over any stick on labels to see if there is a 'hollow' bit underneath...
Under rubber feet or gromits...take 'em off if ant there...
Sometimes plastic recesses and protrusions are used to 'clip' parts together.
When I trained my engineers, I always warn them never to use excessive force to take things apart. try & prise the bits apart and 'sense' where the restriction is and investigate that area...
Is it possible that the disk within has dislodged and is jamming the parts together? Try putting the set on its side, holding the DVD cover together and tapping it with the handle of a screwdriver and see if the disk moves...
Whatever, I wish you well with resolving the problem...