PC fan keeps coming on ................

[Necromancer]

PS. Forgot to say that most 'bigger' desktops have a 'System' fan too - usually located at the rear to pull air in - quite slow revving usually, but worth a check that its actually running when the noise isnt apparent !

Again, I'not aware of variable speed option - but your system may be sophisticated and react to temp' increases...

Have you RTM'ed ? (Read the Manual    )

[casalguidi]

You could get your son to do whatever he does and stand over it to listen where the noise is coming from 

Good thinking Gadget ........................ tried that and it isn't happening LOL - perhaps when the room and/or PC are hotter (it is usually in the small hours when he's home from work and the PC may have been on 18hrs or so by then )

Does the case get hot

Not sure (it's not now) ................. will investigate

Scroppers - it didn't come with a manual and there is nothing (or nothing that I can find) in help

We will see what happens later

Casalguidi

[Gadget]

Hope you can sort it because if it is the same problem as mine, it eventuallly just dies and then you have to do a transplant   

Maybe the new hard drive was too big for the fan and/or power supply unit

Gadget

[Little Nell]

We had the power supply fan fail on one of our PCs a few years ago - it was easy to get a replacement and fit it (well, from my point of view it was - himself visited the local shop and came home with correct fan and fitted it!   )

The next PC went through an upgrade - new faster processer fitted and boy, it hated hot, humid weather thereafter.  We only turned it on out of dire necessity and even then turned a fan on it first!  It was moved to a different location this year and behaved slightly better but did occasionally throw a wobbly - it froze completely and had to be turned off at the wall (otherwise it turned itself back on again!)

From my experience, many older PCs (even just a few months it would seem) do not like hot, humid weather and nor do they like possibly running faster than they were originally designed - especially for 18 hours at a time!  

Nell

[downside]

Hi casalguidi

Are you sure this not the CDROM making the noise?  Certainly when I put a CD in the player it makes noise similar to fan blasting away.  If you say you hear the noise when your son plays a game from a CD is it not logical that the CDROM is making the noise?

Could be entirely wrong though. 

downside

[casalguidi]

If you say you hear the noise when your son plays a game from a CD is it not logical that the CDROM is making the noise?

When it was having a hissy fit the other day, he said "Oh yeah, I can't play "Champ" because that thing starts up every time I load it" .................. as I mentioned, this would be in the early hours when everybody else is asleep (or trying to sleep) .................... so I haven't actually heard that myself but I'll take his word for it ....................... no point arguing with 19 year olds

It has behaved impeccably today (so far) but then it is much cooler so am wondering if we have a similar problem to Little Nell

Am loathe to move it to another room ...................... would be harder to "spy" on teenagers

Will be ready to have a good listen as soon as it starts again though.

Casalguidi

[xrchris]

I would have to agree with Downside's diagnosis.

Most average household PC's have the fan run at a constant speed UNLESS there is an option in the BIOS to have fanspeed control turned on at certain levels.

[arnietheother]

Sounds to me like the lubricant in a fan has dried up, causing it to rattle.
I'd follow the advice of stalling each fan momentarily (one at once) in order to identify which fan is causing the noise. 
Be very careful if you're jamming anything into the PSU fan as there's mains voltages in there.
I wouldn't replace a PSU fan but would replace the PSU as a whole unit as this contains other components (electrolytic capacitors) that deteriorate with age & temperature. 

[bodger]

Never had these problems when i was a lad, just had to make sure we had water, oil, & grease and the steam engine would run all day. bodger