In general, from time to time, my phone (Galaxy SII) lightens up its locked screen for 4-5 seconds.

I thought: the reason behind can be to show if some messages or calls are awaiting to be noticed (but, with screen locked, it is pointless anyway, because nothing is shown besides symbol entry screen).

But sometimes it lightens up the screen like 3 times in a minute, over 15 minutes.

Why it does that?

  • 1
    Some application or widget is trying to wake up periodically, what ROM are you using? How long has this been going on for?
    – t0mm13b
    Jun 26, 2012 at 21:49
  • @t0mm13b: Quite long. ROM is original, so its Android 2.x. I now realised, that signal strenght here is sometimes ZERO, or ONE BAR. And it may constantly fluctuate between 0 and 1 bar from time to time. Maybe going from 0 to 1 is the reason of lighten up the screen?
    – Muller
    Jun 26, 2012 at 22:06
  • Hardware/radio issue? Have you tried another handset, swap out your simcard and put into the other handset to see what signal you're getting. If signal is good, then can easily pin this down to the hardware issue... was it dropped recently?
    – t0mm13b
    Jun 26, 2012 at 22:18

4 Answers 4


Try uninstalling some applications. The same thing happened to me and I fixed it by uninstalling my most recently installed app.


Try BetterBatteryStats or GSam Battery Monitor Pro. Both apps can provide you information on which apps/processes/services are initiating wakelocks, how many times they are doing it and how long they are keeping the device from going into a deep sleep. This may help you identify if it's an app or a system process that is going crazy and waking your phone when it should be idle. They both have free versions but I've only used the pro version so I'm not sure if the free versions will accomplish the same thing.


I am one of responsible developer of UzumApps. We developed app called "wakelock detector"(WLD) for showing statistics of wakelock usage. It is an alternative app for BetterBatteryStats or GSam Monitor.

If your screen lightens up randomly, then I think some app is holding "FULL_WAKE_LOCK" with ACQUIRE_CAUSES_WAKEUP flag, Check : PowerManager

Our app shows "full_wake_lock" statistics also, which will help you to determine the suspicious app. Most probably it will be the currently running process. WLD at GooglePlay

  • 2
    The site policy regarding disclosure in promotions has been noted on your posts before. Please read and understand that FAQ section, particularly the point noting "you must disclose your affiliation in your answers". Also make note of the point stating "If a huge percentage of your posts include a mention of your product or website, you're probably here for the wrong reasons", as thus far all of your answers promote your app. Mar 18, 2013 at 14:39
  • sorry, I did not mean to promote the app, I changed the post and I mentioned the feature (showing full_wake_locks), which could help to find answer for this post
    – UzumApps
    Mar 19, 2013 at 6:13

This happened to me, Samsung Galaxy S3, was killing the battery. After chasing my tail WRT applications, I found a post about the power connector on the bottom of the phone. If it gets slightly bent down it will cause a problem (short against something I assume) and cause the screen to intermittently become active. Take a non-conductive (NOT METAL) thin piece of something and VERY GENTLY move the power connector so it is centered in the hole where it sits. Then try hooking up the power charger; it is easy to move it too much, so the it can't plug in. The idea is to center the connector in the hole. If this looks beyond you, find your nearest friendly geek. Fixes the problem immediately.

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