On Tue, 12 Feb 2008 03:28:52 -0800 (PST), blackhead
<larryharson.RemoveThis@softhome.net> wrote:
>I have a fan on a heatsink on an old 300Mhz AMD socket 7
>microprocessor. When it starts up, I can barely hear it but after 5
>mins it begines to make a whining sound so obviously the heat has
>something to do with it but why?
The fan whines because the bearing is worn out or at least
dried out. If the system is intended to be redeployed for
any length of time it would be prudent now to replace that
fan, largely because the typical fan of that era was a small
higher RPM piece of junk in the first place.
I'd imagine that when it first starts up it is running so
poorly that it's slow, while it eventually comes up to a
high enough speed to overcome the magnetic field because of
a slight imbalance. This may not be the problem, it could
just be expansion of the bearing from heat but either way
the fan needs lubed now just to keep it from further
destroying itself, but ideally the system not ran until a
more reliable fan is installed. Remember that if the fan
completely fails the system will be nice and quiet, possibly
an unnoticed failure - while the processor is baking itself
near death. Socket 7 era systems didn't have any kind of
overheating shutdown protection for the processor.
You could probably get something like the following and
undervolt it to somewhere in a 5 to 7 volt range to increase
fan lifespan and greatly reduce noise. Most modestly sized
socket 370 heatsinks will work on socket 7 if they use the
single middle socket clip style.
http://www.directron.com/aluminumfan.html
If you just want a new fan and to reuse the rest of the
sink, it might be slightly cheaper but not much.
>> Stay informed about: Why does my 10 year old fan whine? 
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