Hello donpedro,
There is a metal disc attached to the centre of the turntable; mine is red.
You can unscrew this metal disc; it’s best to try using sheer muscle power first.
Once you’ve done that, you can remove the entire turntable, but be careful not to mix up the order of the discs. Once the turntable is removed, you’ll be able to access the two screws that hold the casing together.
Otherwise, in my case, it was just the hand brake that had slipped. If there’s a fault with the electronics or any other mechanical part, I can’t help either.
But it usually helps to take a close look at the mechanics inside; perhaps you’ll spot something out of the ordinary.
Regards, henri