High pitched noise mysteries on X61...

[zsero]

I own an X61, which is making a high pitched electric noise every time I run it on battery. It's loud enough that in a lecture theater someone sitting next to me usually notices it. In characteristics it's close to what cheap LCD panels or no-name PC power supplies produce, and it's really similar to one of my former video cards which just started producing this noise before finally braking down.

Here comes the crazy bits:
- It only produces noise when the front wireless switch is ON
- BUT Still produces the noise even if both the bluetooth and wifi cards are disconnected
- You can hear it while on an idle desktop you move the mouse slightly (if you do nothing it's not present)
- it's not coming from the speaker (it's the same with disconnected speaker)

And the real crazy part:
- As my laptop is still in warranty, I had an on-site service where an engineer changed the system board to a refurbished one, and guess what? Nothing changed!
With the engineer we disconnected:
- the display
- the wifi and bluetooth cards
- the CMOS battery
- the hard drive (and started from an external USB Ubuntu LiveCD).
- one RAM at a time
- internal speaker
- and swapped batteries

BUT still the same noise! It's not that I am too sensitive to high pitched noises, even the engineer could hear it clearly. As I know I have tried everything, but no results. On my friend's X61, of course this noise is not present at all! It's present both under Windows and under Ubuntu, but only if the front wireless switch is ON. As far as I could locate the source, it's coming from somewhere under the heatsink, possibly the CPU or NB, but I cannot locate it clearly.

Can someone tell me, why is this thing happening, and why it didn't help using a new (OK, refurbished) system board? It cannot be any software problem, as it's the same under Linux and Windows.

[virge]

Try updating your BIOS. One of the recent BIOS updates has something aimed at correcting this or at least making it better.


Also read: http://forum.thinkpads.com/viewtopic.php?f=30&t=61930