I am using samsung galaxy J5, 2015. I just got it and have tried several alarm clock app. They all have one problem. When I set them to vibrate (sound off) in the morning, they don't do anything. Until I use the cell phone (swipe the screen) first thing in the morning, then they start to vibrate! They can't wake up in the morning! But this problem happens to several app already. I haven't found one that doesn't have this problem. I think maybe this cell phone has some sort of restrictions or it's defect? Like some cell phone has sleep mode? I already disable the "Do not disturb" mode. There are some other minor problem, like I want sound off and vibrate only, but one app just has both sound and vibration on anyway, even when I already turn off the system sound, media sound, and the individual sound for this app. But this is minor. One problem at a time. Does anyone know what is going on? " This cell phone come with default clock that has alarm clock function but it is too simple. It doesn't have repeat, doesn't have sound off and vibration only, doesn't have "no snooze, just auto dismiss." According to gsmarena.com, it is running on "Android OS, v5.1 (Lollipop). I have not upgrade it so it should be.