Martin Laberge mlsoft at
Sat May 17 19:11:35 BST 2008

On Saturday 17 May 2008 13:01:25 Nigel Henry wrote:
> On Saturday 17 May 2008 17:14, Martin Laberge wrote:
> > On Saturday 17 May 2008 06:47:48 Bill Vance wrote:
> > > Howdy;
> > >
> > > I have a very annoying two tone alarm going off, right now.
> > >
> > > Its not going out over the sound card.  Any way to find out what's
> > > going on, how turn it off, etc?  It goes away during shutdown but
> > > returns shortly after reboot, without the slightest hint or clue as
> > > to the cause.....:-(
> > >
> > > Bill
> >
> > I think this the OverHeat alarm, warning you to shutdown now
> > or burn your system. on my machine, this shutdown the system
> > after a few minutes if i dont do it.
> >
> > Check the fan of the CPU and be sure it is properly installed
> > and it is clean. Or check the fan of the power supply,
> > it may be full of dust.
> > --
> > Martin Laberge
> I do remember getting the two tones a while back, and may well have been the 
> bearings of the PSU fan on my not so expensive i-Friend machine ran out of 
> oil, resulting in the fan stopping. thankfully the PSU has a thermal cutout, 
> which just resulted in the machine shutting down abruptly.
> At the time I was puzzled as to why the machine had shutdown, but taking the 
> cover off, restarting it after a few minutes, and looking at the works, I saw 
> that the PSU fan was a no-go. Sometime later after having stripped down the 
> PSU, cleaned out all the dust from it, and having re-lubricated the bearing 
> on the fan (using musical instrument oil, which is all I had at hand, and 
> which had a hypodermic needle type applicator for the oil, and very usefull 
> when applying oil to small moving parts) I re-installed the PSU, and prayed.
> The machine has been running for between 18 months, and 2 years now, with no 
> further problems.
> It's always a good idea to get the dust out of the machine from time to time, 
> and do this perhaps every 6 months. Machine with cover off in the back yard, 
> vacuum cleaner on blow ( banging the hose a bit to get the vacuumed in dust 
> out of it), then go for it. It's simply amazing how much dust builds up on 
> fan blades, and gets pulled onto the CPU heatsink by it's fan, and certainly 
> there's a whole bunch of dust comes out of the PSU unit.
> I try to keep away from the optical drives, and the floppy drive, in case I 
> should blow dust into them.
> I did see mention that spinning the fans when doing this cleanout operation 
> could cause the creation of electricity feeding back into the PSU. I'm not 
> too sure about that. Servo's create a voltage when spun, but whether that 
> applies to fans in the computer I don't know, and havn't had any problems 
> myself.
> I also thought of connecting a ground/earth connection to the machine, when 
> doing the vacuum cleaner dust blowout, as I believe there can be some static 
> electricity buildup from fast moving air. My ground lead wasn't long enough 
> to reach the back yard, so hoped that there would be no problems. I did see 
> suggested though to allow some minutes after blowing out all the dust, before 
> rebooting the now dust free machine.
> Anyway I have had no problems using the vacuum cleaner on blow on my machines, 
> to clean them out.
> I suppose there will be some feedback on my comments, but as it's the weekend 
> I'm game for it.
> Nigel.

I should add, to your excellent description, that these events seems to
occur frequently when the season changes.

in winter, no problem as ambient temp is low,
but summer arrives, then ambient temp is higher
and the fan do not follow.

the problem was there before, but not apparent
due to winter low ambient temp around the computer.

Martin Laberge
mlsoft at

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