[LAU] thinkpad t61 noise

[rosea grammostola]

Hey,

My thinkpad t61 makes a high frequency sound, pipipipipippi, not very
loud. Funny thing, when I stick in the usb mouse, it's gone... I only
have this issue when on battery. Suggestions for solution?

Is it right that there is one fan in the T61, on the left of the
keyboard? Then a other noise source might be the hdd on the right.
It's not that my T61 is very noisy, it isn't very silent either. Maybe
I could change the hdd.

Best regards,

\r