[ltp] Chirping noises when running on high throttle

[David Siska]

Dear All,

I have an IBM R40 2681-HSG and its making strange chirping / buzzing noises. 
It's definitely not the harddisk (you can spin it down and still hear the 
noise) and its definitely not the fan, since one can hear that going on and 
off ocassionally. 

The funny thing is, when I do 
"echo 7 > /proc/acpi/processor/CPU/throttling" 
I can't hear the noise anymore, but with each step closer to 0 (i.e. full 
throttle) it gets louder and louder. Also it seems to be louder when I use 
the touchpad, or the mini-joystick between the keys. 

I've tried several 2.4 series kernels and it's all the same really. I've tried 
searching google, but it's not obvious what to search for, since each person 
would probably use different word to describe the high freq. 
"drrzzrrrzzdrrzzz" noise.  All I found was this page 

http://hardwarecentral.dealtime.com/xPR-IBM_ThinkPad_T40_2373_237319U~RD-103020400260

The guy found something rather similar to my problem in that the noise seems 
to be comming from the region under the upper left of the keyboard. Anyway 
does anyone have any ideas? Anyone seen something similar? Solutions?

Many thanks,
David

Appendix: quote from the article:

<quote>
Original problem: I encountered some noise issues with my T40: power system, 
hard disk, and motherboard. My T40 made strange buzzing sounds when plugged 
into AC. After some experimentation, I determined that the AC adapter (FRU 
08K205) was the culprit. Using a compatible IBM AC adapter (FRU 02K???) that 
shipped with the T23, I was able to eliminate the noise from the T40. 
However, the new AC adapter makes a buzzing noise when it is plugged into the 
wall socket but not powering the T40. This is similar to problems I had with 
the AC adapters in the Dell Latitude D600 series notebooks. The T40 also 
makes a small amount of noise when it is in standby mode and disconnected 
from AC power. The noise again appears to originate from an area near where 
the AC adapter plugs into the T40 unit. 
 
UPDATE: I have isolated the source of this mysterious noise to the USB Root 
Controler. Disabling power management on the USB Root Controler in the 
Windows XP hardware manager causes the noise to go away. 
 
Original Problem: I was unable to isolate the final source of noise in my T40. 
My best description for this noise is a "chirping" sound, similar to what a 
bird might make. I attempted to isolate the source by removing the keyboard 
and palm rests on my T40. The noise appears to emanate from a region under 
the left part of the keyboard. IBM technicians who examined my ThinkPad 
claimed ignorance as to the nature of this noise. 
</quote>