T60 touchpad noise

Anyone else notice (or can look for this). My T60 has a quiet high pitch noise. It can be heard best by placing one's ear close to on the left side of the wrist area. (You can hear it from farther but I'm sure not everyone's hearing in this range (very high) is good). The noise gets louder when you move the pointer with either the touchpoint or pad. You can just touch the touchpad to make it change.

So to those with good ears I would like to know if this is normal. Its not that bad I guess as the room has to be quiet to hear it at all... but, it is not normal then well perhaps I could get it fixed.

 

I believe this is due to the dynamic switching on the CPU. I do not hear it when I am on AC power, but I do when I'm on battery power.

 

I discovered that as well, however to me that implies a grounding issue. The dynamic switching of the CPU should happen at a freq to high to hear, in addition it is correlated to the use of the touchpad and is still present when you set the power management to not dynamically clock the CPU.

I would say its some strobe of the mouse system at 10 kHz or so which is coupling into the lines that drive the speaker directly. I'm guessing that not because I can localize it with my ear to the speakers, but rather simply because its the only transducer of electrical noise that would be present without a ground that I can think of...

 

Does this noise really bother you though? Because I mean, I have sensitive hearing and I can only hear that noise when I am in a dead-quiet room. In a regular classroom with ambient noise and the lecturing I can't hear it.

 

Right its only bothersome in a quiet room. Just because its minor doesn't mean I wouldn't want to fix it. In any case, thanks for letting me know its common.

 

http://forum.notebookreview.com/showthread.php?t=90335

Maybe you should try that? I'll try it later.

EDIT: Seems to work for me!

 

I had to try it twice to even hear it. Is it really bothering you that much? I highly doubt Lenovo will touch it and I doubt that you can fix it yourself.

Matt

 

That thread is pretty extensive thanks. It certainly must be coupling to a transducer of some sort, at a few kHz. Its possible the power management is strobed at that rate. It is good to know.

You are claiming the USB power management fixed it for you? It didn't do anything for me I turned it off on all 5 tabs. In any case as noted this isn't a very loud noise. I just am a curious person.

 

In my friend's notebook it is clearly coupling to the speaker if that is all, it is possible in principle to fix it with some careful, careful work shielding cables. I could do this, but I doubt I would bother, as noted in the T60's case its not loud in my friend's case its very loud.