Tracking down the source of a high pitched sound at the edge of hearing

[cdev]

Here is a new development, today and yesterday its been relatively cold and since I usually keep the house less heated than many the ambient temp has been kind of cool.. today and yesterday the whine has been almost inaudible. I wonder how adding some additional ventilation (I can do that without even cracking the case open temporarily by taping an additional 120 mm case fan to the exterior vent as an experiment.) will give that a try.

[SilverSolder]

How about a small electret mic at the end of a stick, plugged into your scope, and probe around until the offending component is found?

[HB9EVI]

I don't know why you bother with that piece. Since it's already an old board, drop it, sell it on the auction platform of your choice to the next who maybe doesn't hear it no more and get a new/second hand one.

already a while ago I tried to figure out, why the DigitalDevice DVB-S2 card drops in a blocked state after 4-6 weeks on my linux server; only a restart fixed the issue. Turned out, it was the board (Asus P5Q-SE2) - even if I tried every kind of trick, new kernels, different configs, different module options, I couldn't get a hand on it.
so one day threw the board on an auction platform, sold it for 50 bucks and got me an AMD board. Never heard anything from the buyer about problems, neither did my satellite card reproduce the issue on the new board

[NiHaoMike]

The issue can still rear its ugly head if you use external audio amplifiers - ground loops / common mode effects between the external amp and the PC can be a real b!tch...

Not likely with modern amplifiers that use HDMI.

[SilverSolder]

The issue can still rear its ugly head if you use external audio amplifiers - ground loops / common mode effects between the external amp and the PC can be a real b!tch...

Not likely with modern amplifiers that use HDMI.

Is the signal digital with those?

[cdev]

The monitor I just got is very strange, it shows up as HDMI audio but there are no speakers and no amplifier. I wonder if it has the circuitry and could be used.

[wraper]

The monitor I just got is very strange, it shows up as HDMI audio but there are no speakers and no amplifier. I wonder if it has the circuitry and could be used.

What model? Many monitors have 3.5mm audio output.

[NiHaoMike]

Is the signal digital with those?

HDMI only supports digital signals.