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Punch Card
Posts: 7
Registered: ‎07-13-2012
Location: California
Views: 5,743
Message 1 of 4

t420s static noise

Hi all,


So my t420s has this weird, stati-like noise that seems to come from the fan. No, it is not the fan (actually I don't mind the fan at all) It isn't the speakers either.

It seems to happen when I'm using the battery and as soon as I plug it in, the noise goes away. It's pretty strange. This isn't the first time I hear this on a t420's. Does enyone have this issue? Is it bad? Should I be worried?

Retired Support Specialist
Posts: 229
Registered: ‎05-22-2012
Location: Hong Kong
Views: 5,720
Message 2 of 4

Re: t420s static noise

Hi jonathan1636,

Please try update latest BIOS. If problem remains, please kindly contact local lenovo for machine inspection

Worldwide Support Center phone list for ThinkPad, ThinkCentre and ThinkStation systems

T61 + X201i
Punch Card
Posts: 7
Registered: ‎07-13-2012
Location: California
Views: 5,695
Message 3 of 4

Re: t420s static noise

Hey, thank you! I think it worked. Although I still hear it every now and then.

I will probably still contact them to check it out since my right speaker sounds busted.

Thanks again.

Posts: 10
Registered: ‎04-02-2011
Location: US
Views: 5,616
Message 4 of 4

Re: t420s static noise

Hi Jonathan,


It sounds like coil whine, or "CPU whine". Does it sound anything like any of these clips?:


There's another thread going on about it over here. I'm waiting for a reply on the best way to resolve the issue with my T420s with this problem. I don't just want to send it in and end up with someone unfamiliar with the issue who just replaces the motherboard, doesn't check the new one, the new one has the same problem, and neither I nor Lenovo are any better off...

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