Something wrong in my power button in yamaha psr e443

by Sam

Actually the power button (of my Yamaha PSR E443) isn't working. When I plug the keyboard to electricity, it turns on but the problem is it should wait until I press the power button.

And I can't turn the keyboard off by power button. I have to disconnect it from wall socket directly to turn off it.
Also the auto turn off feature isn't working.
Keyboard turns off at scheduled time but suddenly turns on again!
Does Anyone can help me ???? Thanks :(