It starts a few minutes after bootup. If I touch the casing it abates or stops only to start again a few minutes later. I have a feeling its the fan as I had a similar problem with a PC some years ago.
Is there an easy cure short of replacing the fan?
yep. Open her up, blow the crap out and one drop of light machine oil on any bearings you can access.
If it is just dirt, cleaning may help(air in a can etc...). If the oscillation is due to bearing abrasion... replace it.
Fan failure is directly related to RPM and bearing type. High RPM and sleeve bearing cause early failure. Low RPM and ball bearings last longer. Get one of those if you want your peace... assuming the heatsink can handle the heat with less airflow.
Depends which fan it is. If its the psu one then its a common problem as tese seem to be made to seize or wobble by design. If its one either in the side of a case or the processor one, then this is less common. From experience its normally just something vibrating in sympathy with these, like a screw or some cables touching the case. Really it can be a pain as the usual thing is that when you take the side off it goes away. Brian
As others have said, start by cleaning. Personally I carefully remove the CPU fan and hoover the crap out of the heatsink. Many will tell you not to use a hoover because of possible static discharge so it's your choice. That might be enough for the fan to then run slowly again (I can tell how dirty my PC is from the noise it makes) and go quiet.
If the CPU fan has actually gone, replace it. Hopefully you can find a replacement fan from somewhere like "Quiet PC" which fits your heatsink. Frustratingly some fan/heatsink combos seem to be designed to stop you replacing the fan and you may have to replace the whole heatsink and fan but at least they're not too expensive.
BTW, watch out for something which caught me. I recently fitted an Arctic (the brand) heatsink/fan and it came "preloaded" with heatsink compound. But the compound was not protected in any way and I didn't spot this so put the heatsink to one side, heatsink compound side down of course, resulting in a patch of compound on the table and no longer on the heatsink. I happen to have heatsink compound anyway but I would have been buggered if I hadn't.
Paul DS.
That might be a resonance. Noisey fans either quiet down after a minute or two and stay quiet or never quiet down. By "touch" do you mean gentle lay on of fingers or a light tap? Laying on of fingers would point to a resonance. a tap to a noisey fan.
If it is one of the fans (PSU, CPU, Video card, case...) then the only real cure is a replacement. A tiny, trace, drop of light machine oil in the bearing, if you can get at it, might help for a while.
Could be a loose screw somewhere or an internal card or even cable connectors touching the motherboard or fan. If there's no loose screws on the outside of the case, I'd take the side panel off, then wait until the noise starts again and try gently touching everything inside with the (non metal) handle of a screwdriver until it stopped again. Always worth trying before jumping in and replacing the fan. Sometimes even just taking the side panel off and putting it back on again can cure it.
As others have said, it's a slight imbalance which is causing the casing to resonate. If you want a quick fix without any dismantling, cleaning, lubricating, etc. try applying some damping to the casing at the point where you have to touch it to stop the noise. A dollop of plastitac (sp?) or similar may do the trick. The extra mass will change the resonant frequency so that it's less likely to be excited by the fan, and the damping will reduce the amplitude if it *does* still resonate.
The extra mass will change the
Good idea! Never thought of that!
May be the smaller fan on the graphics card.
I would avoid machine oil (and definitely 'WD-40"!) in favour of clock or even watch oil. Machine oil tends to become too gummy over time.
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