ASUS A7N8X-X: high frequency noise by an induction coil !

Hello,

A high frequency noise is generated by an induction coil of the ASUS
A7N8X-X. The noise occurs only when I am logged in WinXP (e.g. not when in
FreeBSD), when accessing particular web pages (e.g. http://uk.asus.com/ is
one of them, while http://www.asus.com/ is not !!), or when maximizing
particular, already running, apps (MSN messenger is one of them). In some
cases the noise persists even after closing down the web page or app.

Moreover, a "clicking" noise of less applitude is also generated by the
coil at all times, which is audible especially when I move the mouse.

The paradox is that when the CPU is not idle but operates in loads of more
than 3% the noises cease, and they are coming back again when the load is
back to 0%.
(I have monitored the voltage variation when the noise is or is not occuring
and I have seen slight differences (e.g 0.1- 0.2 Volts). I am using a
Qtechnology PSU, which is of a reletively good quality. I have also used for
testing purposes a different one to exclude the possibility that it is a PSU
related problem (it can be though)).

I have also tried on another graphics card, and striped the computer down to
only necessary components (e.g. just grapfics card and a hard disk). I also
made sure that it is not a failed induction coil problem by returning the
m/b back to the retailer and using a new one.All the latest drivers have
been installed as well.

Have you come accross what I have described above?Any solutions?

TIA

ASUS A7N8X-X (revision 2.00, BIOS 1009 rev.), AMD Barton 2800XP+, Crucial
512MB 184Pin PC3200 DDRRAM ECC Unbuf CL3, Zalman CNPS6000-CU, Barracuda
7200.7 200GB, Gigabyte (ATI) Radeon 9000, QTechnology Ultra-Quiet ATX PSU
300W.

"jimjim" wrote in message k...
Hello,

A high frequency noise is generated by an induction coil of the ASUS
A7N8X-X. The noise occurs only when I am logged in WinXP (e.g. not when in
FreeBSD), when accessing particular web pages (e.g. http://uk.asus.com/ is
one of them, while http://www.asus.com/ is not !!), or when maximizing
particular, already running, apps (MSN messenger is one of them). In some
cases the noise persists even after closing down the web page or app.

Moreover, a "clicking" noise of less applitude is also generated by the
coil at all times, which is audible especially when I move the mouse.

The paradox is that when the CPU is not idle but operates in loads of more
than 3% the noises cease, and they are coming back again when the load is
back to 0%.
(I have monitored the voltage variation when the noise is or is not occuring
and I have seen slight differences (e.g 0.1- 0.2 Volts). I am using a
Qtechnology PSU, which is of a reletively good quality. I have also used for
testing purposes a different one to exclude the possibility that it is a PSU
related problem (it can be though)).

I have also tried on another graphics card, and striped the computer down to
only necessary components (e.g. just grapfics card and a hard disk). I also
made sure that it is not a failed induction coil problem by returning the
m/b back to the retailer and using a new one.All the latest drivers have
been installed as well.


Have you come accross what I have described above?Any solutions?

TIA

ASUS A7N8X-X (revision 2.00, BIOS 1009 rev.), AMD Barton 2800XP+, Crucial
512MB 184Pin PC3200 DDRRAM ECC Unbuf CL3, Zalman CNPS6000-CU, Barracuda
7200.7 200GB, Gigabyte (ATI) Radeon 9000, QTechnology Ultra-Quiet ATX PSU
300W.


Probably one of the toroidal inductors on the motherboard is singing
under certain load conditions. You can tell which one by touch or by
listening to each one through a non-conductive tube, such as a large
drinking straw. Once you find the component you can't bath it in
Silicone RTV compound and that should dampen out the vibration.

arnie