Android AlarmManager stops when activity die

There could be a couple of different issues at work here:

• The type of alarm you are requesting (ELAPSED_REALTIME) will not wake up the device to deliver the alarm. Instead, if it expires while the device is sleeping it will be delivered the next time the device wakes.
• The triggerAtMillis value of 1000 is requesting the first alarm at 1 second after boot of the device. If the device has already been up and running and you request this alarm, the first alarm may not fire and could cause the subsequent ones to not get scheduled. This is just a guess, I've not verified by looking at the 4.4.4 AOSP sources

The alarm handling was changed in API 19 (Android 4.4) to handle collating of alarm timers (all are inexact by default) and this change could have affected things for the 2nd bullet. You might try changing the triggerAtMillis value to be (SystemClock.elapsedRealtime() + 1000)

Note that if you need the device to wake from sleep, you'll need to use a _WAKEUP alarm variant and also have your BroadcastReceiver take a wake lock which your Service or Activity releases when it is done handling the alarm.

Check whether the app is in stopped state.When the app is in stopped state it wont receive any alarm or events.

Also, I guess it might be OEM/manufacturer specific firmware/OS issue.To check whether the alarm has being actually schedule use adb shell dumpsys alarm and check whether your app alarm has being actually scheduled.

To check whether it is in stopped state use the following command:

adb shell dumpsys package "com.package.name" and check "stopped=true"

To know more about stopped state refer:

Launch controls on stopped applications

Starting from Android 3.1, the system's package manager keeps track of applications that are in a stopped state and provides a means of controlling their launch from background processes and other applications.

Note that an application's stopped state is not the same as an Activity's stopped state. The system manages those two stopped states separately.

The platform defines two new intent flags that let a sender specify whether the Intent should be allowed to activate components in stopped application.

FLAG_INCLUDE_STOPPED_PACKAGES — Include intent filters of stopped applications in the list of potential targets to resolve against. FLAG_EXCLUDE_STOPPED_PACKAGES — Exclude intent filters of stopped applications from the list of potential targets. When neither or both of these flags is defined in an intent, the default behavior is to include filters of stopped applications in the list of potential targets.

Note that the system adds FLAG_EXCLUDE_STOPPED_PACKAGES to all broadcast intents. It does this to prevent broadcasts from background services from inadvertently or unnecessarily launching components of stoppped applications. A background service or application can override this behavior by adding the FLAG_INCLUDE_STOPPED_PACKAGES flag to broadcast intents that should be allowed to activate stopped applications.

Applications are in a stopped state when they are first installed but are not yet launched and when they are manually stopped by the user (in Manage Applications).

Please note stopped state is different from app process not running.

This is only a guess but I think the issue has to do with the API. Starting with KitKat, the system messes up the AlarmManager. Perhaps consider trying using something else for systems at abd above kitkat.

"Note: Beginning with API 19 (KITKAT) alarm delivery is inexact: the OS will shift alarms in order to minimize wakeups and battery use. There are new APIs to support applications which need strict delivery guarantees; see setWindow(int, long, long, PendingIntent) and setExact(int, long, PendingIntent). Applications whose targetSdkVersion is earlier than API 19 will continue to see the previous behavior in which all alarms are delivered exactly when requested. "

Taken from http://developer.android.com/reference/android/app/AlarmManager.html