laptop high-pitched noise/hum

[kelvinc]

i've got a compaq laptop for 6 months now, and only recently i've noticed that it emits a high-pitched noise/hum on batteries *and* when it's plugged in. i've taken a vacuum to the fans and cleaned out the dust, but now i don't think that's the cause.

any ideas?

[SLATYE]

Normally this is just something in the voltage regulators vibrating at very high speed (especially if it does tend to change depending on CPU load). It affects desktop mainboards too. I've found that on some laptops it's also caused by the speakers - this can often be fixed just by disabling the microphone/line-in.

Unfortunately, there's no easy solution (I don't think there's any solution which costs less than replacing the whole mainboard and power supply).