On 2010-11-19, Ignoramus5827 wrote:
I have a couple of devices with very noisy and annoying fans. One is
an old laptop and another is a car inverter. In both, fans make a very
annoying, inconsistent, and rattling sound. Before taking those things
apart etc, I wanted to double check what is the typical cause of this
and how to deal with them.

A little update. I received the 20 dB replacement fan from
Digikey. The cost was $11.46. I tried it on a power supply and it was
as quiet as advertised. I installed it in the inverter and the
difference was nothing short of dramatic. I have to make an effort to
hear that fan, it is almost silent.

Note that the CFM rating matches the original. The difference is
mostly cost, this fan probably cost $3 to produce and the original, I
would guess, 50 cents.

With a 50k hours service life, even adjusted downwards for running in
hot summers heat, this will clearly last me a very long time. Assuming
1 hour per day use of inverter, and being conservative about fan life,
it would be 20,000 days, or 54 years. Then, at the age of 94, I might
splurge for a new inverter. ;-)

We'll see how it really works out though.

i