Question SM-G998U - Odd buzzing/vibrating when set down

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Senior Member
Nov 12, 2008
I've begun noticing odd behavior w/ my S21 Ultra when I set it down on a flat surface.

Intermittently, I will hear what I initially thought was static/buzzing from a speaker. It's actually the phone buzzing/vibrating. This is not related to a notification, as I can reproduce it by setting the phone down a few times.

It appears to be the haptic motor running at a low frequency for no reason at all, and it will stop if I pick it up. You can feel the vibration coming from the top center of the device, and it creates an audible hum from whatever surface the phone rests on.

Anyone else seen similar?

I wouldn't think it's a software issue, but I may consider a factory reset. I'm running the U1 firmware on the U variant, but that doesn't seem like a logical cause.


Senior Member
Jun 23, 2013
I'd just check the settings menu called "system sound/vibration control" and then look at what's enabled for device vibration. Try disabling the vibration access to just ONE thing there at a time and see which one stops the idle vibration from happening.

If disabling one of those options prevents the idle vibration, then you'll know what to look into more specifically to resolve the issue. But without that information, there's not really a way that anyone here can diagnose the exact issue as it also might just be a screwed up/malware/other virus app that was installed... =(.

A family member of mine has an obsession with installing virus apps from the Play Store and then always complains about their phone being slow lol. So if you install more than 40 apps from the Play Store, then you're in the same boat as my family member (who for some dumb reason has over 100 apps installed from the Play Store lmao).
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