Yamaha CDX493 CD player?

I have a Yamaha CDX493 CD player, it was working ok, now the cd tray does not open when buttons are pressed, checked the belt that's fine I can open it by turning gear by hand just to start it off and then it opens as normal I can put a cd in the tray and it shuts and plays fine but when I try to open again same thing happens, it gets stuck I then have to take cover off and remove the cd move the tray gear 2 clicks on the gear and it will then open as normal and close but will not open again
I looked for some sort of adjustment but cannot see how this is possible any ideas?