Resonance sound (vanishes when opening or touching the case)


Nov 15, 2013

Yesterday my (1 month old) PC started making a sort of whirring resonance sound. It's not extremely loud, but fairly audible coming from the case.

The sound stops if I: open the case (it's the type the side of which can be easily opened without screws) or lift the case off the ground, or tap it gently, or gently touch a component like the graphics card. It's not consistent. The sound *can* start again with the case open. Sometimes simply moving the case door causes it to start or stop.

I don't think it's a capacitor, since if it was, I don't think moving the case door would cause it to stop (or would it).

It was difficult to diagnose, since as I said it was not consistent, and opening the case often stopped it. I did the following however:

_ Completely removed graphics card (it was my first guess since touching it often caused the sound to stop). I connected to mobo's graphics adapter. Sound still there.
_ Once I managed to get the sound on with the case open, I tried all the fans. I would quickly stop each one with a q-tip. Did that with the all the case fans and the CPU fan (I made sure CPU load was 0 and temperatures were below before doing this). Stopping those fans had no effect on the noise. I couldn't do this to the PSU fan, because that's at the bottom of the case, and as soon as I put the case sideways, the noise stopped.
_ I unplugged the PSU, did a quick look at it, but didn't notice anything out of the ordinary. Put it back. The sound was gone for a few hours, so I thought that did the trick, but it came back again this evening.
_ I did a sanity check on loose wires, etc... but there doesn't seem to be anything particularly wrong.

Any idea what could be the issue? Other than the PSU, the only thing I can think of is the HDD (I have an SSD and an HDD).
Any suggestions on how to proceed. The problem is it's difficult to diagnso because it's not consistent.