1. Check the turntable surface for paint removing and
rusting condition;
2. Check the locking screws on the back side for
looseness;
3. Check if the chain of locking pin is broken or not;
4. Place the turntable in level status, release locking pin,
push the turntable cover with hand to all directions in
order to check if it moves smoothly (if it does not
move smoothly, please release the fixing screw at the
bottom, open the turntable and clear its inside).