Why so much HD activity?

[Peter]

Now the Filemon issue. I'm puzzled by your reply, because I have 7.0

Whatever the cause of that bizarre behaviour, pleased to say it
appears to have cured itself <g>.

BTW - if I can be excused for continuing OT briefly - do you use
Filemon with filters? If so, could you give me any pointers on a few
examples please? Its output is daunting without them! Of course,
entering 'J' was simple enough, and got me references to my new HD.
But I'm sure there are some really clever techniques... Is there a
newsgroup or online forum good for Filemon discussion?

I'm not aware of any, but didn't searched for them either...

 

[Terry Pinnell]

Blowing the dust out won't hurt, but an unbalanced fan wouldn't explain why
the sound goes away when you touch the case (I presume you mean by "case"
the metal box that forms the outer shell of the computer). As for the
bearing, if the fan is coming up to full RPM the bearing is not likely to
be causing a balance problem--if it's a sleeve bearing and it's failing it
would be slowing the fan down, if it's a ball it can make noise for a long
time before it stops functioning as a bearing. I wouldn't try oiling it
unless I was sure that it was the problem--with the machine shut down does
the fan spin freely with no feeling of roughness when you turn it by hand?
If so then the bearing is functional.

If it's sometimes louder and sometimes softer then there could also be a
beat-frequency component resulting from two devices at nearly the same RPM
going in and out of phase with each other.

Thanks, John. As you've probably now seen from my subsequent post, all
now OK. BTW, by 'case', I was referring to the fan case.

 

[Rod Speed]

Thanks. No can of air at hand so used toothbrush and small vacuum
cleaner. Drop of 3-In-One oil, and 'GlueStick' to replace label. Only
snag was that one of 4 threads in h/s had 'gone', so screw was
complexly loose. Found another slightly larger diameter, hacksawed to
correct length, and that seems OK.

Pleased to report now quietened!

Most likely you didnt need to oil it at all and it was just the looseness
of the mounting that was resonating with the hard drive vibration.

 

[J. Clarke]

No, Steve is right, I was mistaken/misleading in my initial
description. Now that I've been more careful and also taken the cover
off, I can clearly see/hear that the 'throbbing' is coming from the
fan mounted on top of the Athlon CPU heat sink.

It's intermittent and it's not consistently the same sound. I can
alter it by touching the case.

If you can alter it by touching the case it's either something loose or a
panel resonance. If it's something loose find out what and tighten it. If
it's a panel resonance there are at least three fixes--different case with
different resonant frequency, alter the RPM of the fan so it's no longer in
resonance with the case, or add some mass and damping to the resonant
panel, which you can do by sticking in some purpose-made soundproofing
(Dynamat Extreme <http://www.dynamat.com/> is the gold standard--"ice and
water shield" that you can get in the roofing section building supply
stores is cheap and works well but read all the fine print, if you go to

I obviously muddied the water by my description, in particular the
distinction about spinning. I was confused partly because I hadn't
realised that activity on this new HD still caused the existing HD LED
to come on, despite being on a new PCI controller. And I had not found
anywhere to connect the little LED that came with the 5.25" mounting
tray, so I was guessing whether the HD was seeking! I now realise that
the existing LED *does* get activated. So I can now definitely state
that this noise is not arising from disk seeking. Which is a relief.
But sorry for causing confusion <g>.

OK, now how to cure the problem. After much googling, it's plainly a
common problem. Largely caused by OEMs fitting cheap fans. Here's a
photo:
http://www.terrypin.dial.pipex.com/Images/NoisyCPUFan.jpg
(Note how my digicam flash managed to freeze the spinning label BTW!
Didn't want to waste time re-booting, given the slowness of that
procedure at present on this system.)

Presumably the fan will come off completely after unscrewing the 4
corner screws? Can I then lubricate it with thin oil by peeling off
that label? And it clearly needs the dust removing. Is that a job best
done by buying a can of pressurised air?

Yes to both. Use a very small quantity of oil. Rather than trying a drop,
flow it down a wire or a needle or something and you'll get more control,
but practice on something else to get the technique down.

For a better solution I suppose I should replace it. It seems to be
6cm square - a standard size? Is it worth buying a more expensive one
with ball bearings?

Panasonic Panaflo (or in the UK Papst/BKM might be more readily
available--they're of about the same quality as Panaflo) with fluid dynamic
bearings. Make sure you get one with about the same flow rate as the
original--if you're not sure err on the side of increased flow. Ball
bearing fans are inherently noisier than FDB fans, and get noisier.

 

[J. Clarke]

An immediate finding is that one of the 4 screws is not 'threading',
IOW is completely loose and cannot be tightened up. However, all the
others are firm (and I've just given them another 1/4 turn). The
'resonance' diagnosis is one possibility, which maybe I could cure
with a replacement fan, or adding a couple of diodes in series with
leads to reduce voltage applied? But how about bearing failure or dust
build-up? As you saw from my photo, there's a fair amount of dust
inside the fan. Could this unbalance it, and - combined with wear on
the presumably cheap bearing - cause this throbbing? It changes every
few minutes, sometimes deeper sometimes higher.

Blowing the dust out won't hurt, but an unbalanced fan wouldn't explain why
the sound goes away when you touch the case (I presume you mean by "case"
the metal box that forms the outer shell of the computer). As for the
bearing, if the fan is coming up to full RPM the bearing is not likely to
be causing a balance problem--if it's a sleeve bearing and it's failing it
would be slowing the fan down, if it's a ball it can make noise for a long
time before it stops functioning as a bearing. I wouldn't try oiling it
unless I was sure that it was the problem--with the machine shut down does
the fan spin freely with no feeling of roughness when you turn it by hand?
If so then the bearing is functional.

If it's sometimes louder and sometimes softer then there could also be a
beat-frequency component resulting from two devices at nearly the same RPM
going in and out of phase with each other.

 

[J. Clarke]

Thanks, John. As you've probably now seen from my subsequent post, all
now OK. BTW, by 'case', I was referring to the fan case.

That explains my confusion. Glad to know it's working properly. I'm kind
of surprised that the glue stick worked--have to try it next time.

 

[Terry Pinnell]

Terry Pinnell wrote:

That explains my confusion. Glad to know it's working properly. I'm kind
of surprised that the glue stick worked--have to try it next time.

Remains to be seen if it *stays* on <g>.

This PC is in my office directly above our lounge. After the repairs,
I worked for an hour or so, delighted that quiet had been restored.
But was then dismayed while sitting in the lounge afterwards to
*still* hear a ryhthmic 'beat' or throbbing ;-(

It's by no means deafening, but is intrusive. I'm aware of it even
while watching TV. It will have to go!

Right now I'm back at my desk. The PC is on the carpet 3 feet away, at
the side of the desk. I can just hear this beat from here, behind the
familiar high frequency fan and HD spinning sound. Kneeling on the
floor with my ear by the PC case, I can hear the beat distinctly, at
about 1 cycle per second. And downstairs in the lounge it's
surprisingly distinct. This is through carpet, underlay and 2 layers
of plasterboard.

So ... it's now becoming clear that I've had at least two
contributions to this noise (triggered or exaggerated by the addition
of my new HD). After eliminating the mechanical noise from the fan
(which itself may have been due to multiple causes, such as bearings,
dust and one loose screw), it seems I'm left with this pesky beat. But
it doesn't appear to be anything I can stop by touching any PC panels,
or even holding the fan itself. So I assume it's some sort of beat in
the air itself, caused by the rpm speeds of various components being
very close together? Rather like 'heterodyning' in radio terms?

I'm not sure what the best approach is. But as one step I think I'm
going to buy a new 60mm CPU fan, which is surely unlikely to be
similar in rpm speed to the present one? Hopefully that will take the
beat frequency out of this apparently sensitive region.

Any further ideas from anyone would be appreciated please.

 

[Terry Pinnell]

If you have more than one location in which you can install your hard disk,
try moving it around--you may be hitting a resonance in the mounting
--moving the disk to a different location can alter the resonant frequency
of the assembly.

Unfortunately that's the only location left for it.

But I'm pretty sure most of the resonance or whatever is coming from
the removable PC side-panel, and I'm thinking about self-adhesive
insulation of some sort.

 

[Rod Speed]

Remains to be seen if it *stays* on <g>.

This PC is in my office directly above our lounge. After the repairs,
I worked for an hour or so, delighted that quiet had been restored.
But was then dismayed while sitting in the lounge afterwards to
*still* hear a ryhthmic 'beat' or throbbing ;-(

It's by no means deafening, but is intrusive. I'm aware of it even
while watching TV. It will have to go!

Right now I'm back at my desk. The PC is on the carpet 3 feet away, at
the side of the desk. I can just hear this beat from here, behind the
familiar high frequency fan and HD spinning sound. Kneeling on the
floor with my ear by the PC case, I can hear the beat distinctly, at
about 1 cycle per second. And downstairs in the lounge it's
surprisingly distinct. This is through carpet, underlay and 2 layers
of plasterboard.

So ... it's now becoming clear that I've had at least two
contributions to this noise (triggered or exaggerated by the addition
of my new HD). After eliminating the mechanical noise from the fan
(which itself may have been due to multiple causes, such as bearings,
dust and one loose screw), it seems I'm left with this pesky beat. But
it doesn't appear to be anything I can stop by touching any PC panels,
or even holding the fan itself. So I assume it's some sort of beat in
the air itself, caused by the rpm speeds of various components being
very close together? Rather like 'heterodyning' in radio terms?

In theory, yes. Hard to believe that the fan speed is that
accurate tho that you get that constant a beat frequency.

What happens to the alleged beat if you put your
finger on the hub of the fan and slow it down a tad ?

I'm not sure what the best approach is.

You basically have to work out where is coming from before
you can say anything much useful about how to stop it.

It would be worth removing the power from the hard drive
just to prove that it is involved. Its possible that something
else got mechanically disturbed in the process of installing
the hard drive in that case.

But as one step I think I'm going to buy a new 60mm CPU fan,
which is surely unlikely to be similar in rpm speed to the present one?

I'm skeptical that its the cpu fan given that its unlikely
that the speed can be as constant as it would have
to be to produce that very low frequency beat.

Hopefully that will take the beat frequency
out of this apparently sensitive region.

Any further ideas from anyone would be appreciated please.

It would be worth trying mounting the hard drive in a different
place in the case if you can if the problem goes away with no
power to the hard drive.

 

[J. Clarke]

Remains to be seen if it *stays* on <g>.

This PC is in my office directly above our lounge. After the repairs,
I worked for an hour or so, delighted that quiet had been restored.
But was then dismayed while sitting in the lounge afterwards to
*still* hear a ryhthmic 'beat' or throbbing ;-(

It's by no means deafening, but is intrusive. I'm aware of it even
while watching TV. It will have to go!

Right now I'm back at my desk. The PC is on the carpet 3 feet away, at
the side of the desk. I can just hear this beat from here, behind the
familiar high frequency fan and HD spinning sound. Kneeling on the
floor with my ear by the PC case, I can hear the beat distinctly, at
about 1 cycle per second. And downstairs in the lounge it's
surprisingly distinct. This is through carpet, underlay and 2 layers
of plasterboard.

So ... it's now becoming clear that I've had at least two
contributions to this noise (triggered or exaggerated by the addition
of my new HD). After eliminating the mechanical noise from the fan
(which itself may have been due to multiple causes, such as bearings,
dust and one loose screw), it seems I'm left with this pesky beat. But
it doesn't appear to be anything I can stop by touching any PC panels,
or even holding the fan itself. So I assume it's some sort of beat in
the air itself, caused by the rpm speeds of various components being
very close together? Rather like 'heterodyning' in radio terms?

I'm not sure what the best approach is. But as one step I think I'm
going to buy a new 60mm CPU fan, which is surely unlikely to be
similar in rpm speed to the present one? Hopefully that will take the
beat frequency out of this apparently sensitive region.

Any further ideas from anyone would be appreciated please.

If you have more than one location in which you can install your hard disk,
try moving it around--you may be hitting a resonance in the mounting
--moving the disk to a different location can alter the resonant frequency
of the assembly.