iPhone alarm clock sometimes doesn't work I can't count how often I overslept since I'm using my iPhone as my main alarm clock. I can't reproduce it and it's happening without any observable frequency of occurrence. Here is all I know:


My iPhone is not jailbroken and I've already done a complete reset for several times.
The volume is loud enough. I test the volume of the alarm clock before I go to sleep and it's definitely loud enough. In addition, the iPhone is lying in a distance of 15 inches from my head.
I'm not sleepwalking, so it's impossible that I turn off the alarm clocks at night. ;)
Most of the time I set three or four alarm clocks with intervals of 15 or 20 minutes. Just to get that I'm so glad I can sleep another 15 minutes - feeling.
As I already mentioned, the malfunction does not always occur. The alarm clock does work sometimes. The first alarm clock goes off at 5:30, another one at 5:45, I get up and go to work. But in 30 % to 50 % of the cases, it does not go off and I'm late for work, in a bad mood and really stressed.
When I realize I have overslept I first have a look at my iPhone. When I unlock it, I see that there is still the message I programmed for the alarm clock to display when activated! Like Get up! or something. That's very strange because it implies that the alarm has been activated but only the message is shown and no sound.
I've got no other problems with my iPhone (besides a synchronizing issue I got the Tumbleweed badge for). Sound is working fine, settings are always applied.
It's not an issue of push-messages being displayed. I first assumed that it could be a push message from Google+ or a news-app I'm using but the malfunction is also occurring without any push-messages being displayed.
I've been searching the net for a solution and found the issue of iPhone alarm clocks going off one hour late. That is not my problem, because - as I already said - the alarm seems to go off, but without sound.
I'm not deaf.


The iPhone:


iPhone 4 32GB
iOS 4.3.5
No jailbreak


I hope one of you has a solution for this problem, because I would feel very strange buying an old school alarm clock. :) But I think I have to, if I can't fix this malfunction of my iPhone.

Thanks in advance.
I have written up a procedure for you to try:


Restore your phone.
Test - if successful go to last.
Take your iPhone to the nearest Apple store and tell them what's happening.
Test the issue with the refurbished iPhone they gave you to replace the one that was malfunctioning - if successful go to last.
Enjoy your "15 more minutes" feeling.


Failing all of these, your alarm is going off and you're sleeping through it because you stayed up too late playing WoW, drinking, coding, whatever. It eventually stops making noise and leaves the message on the screen. Try placing the phone across the room so you have to get up to turn it off. See if that helps. Either way, now you have a newly refurbished iPhone 4.

Please forgive the snarky nature of this answer. I wrote it after my alarm didn't go off in the morning due to a push notification.