Cooling fan questions & more

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Hi to all,

I have an old Compaq Presario 700US. I have several questions that I hope
anybody can answer.

Question 1.   The laptop has 2 cooling fans.  One on the left side on the
heat spreader(heat sink??) and one in the upper right hand side of the case.
The upper right doesn't move at all. So it needs to be replaced.   But the
fan on the heat spreader starts and runs after about 30 seconds after
Is the fan controlled by software or a hardware thermostat device? Or does
it need to be replaced too?

Question 2.  The stuff that I've read says that the thermal pad needs to be
replaced every time the heat spreader is removed from the processor.
Problem is that Compaq (HP) will sell them,  but only in the quantity of 100
for a hefty $185. I only need one or two.  No one, even where I live in
Houston Texas has them.  Could I substitute thermal grease (i.e. Arctic
Silver 5 or Ceramic) without any concerns?

Question 3.  I''ve heard  rumor that some laptop parts sold by resellers as
new are not even refurbished, but pulled out of discarded laptops tested and
then resold. True/False???



Bye for now,

Re: Cooling fan questions & more

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There are usually two fans, one for the CPU (often cooling a radiator fed by
heat pipes from the CPU), the other for the graphics processor (usually
operates directly).
The fan speed is usually a function of the processor temperatures and
usually controlled by a separate bit of hardware to the rest of the PC (but
may get input as to how loaded the procesors are).

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The thermal pads are actually phase change thermal compound.  This is
generally available and comes in something that looks like a Pritt Stick.
Thermal compounds of whatever type should be renewed.

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Could be.

Re: Cooling fan questions & more

The fans in laptops are almost always controlled, both to reduce noise
and power consumption, and it's possible that the one that isn't moving
isn't moving because the temp. threshold has not been reached.  There
are some laptops on which the fans almost never come on (and others that
will over heat even if the fan is forced to run constantly).  Many
manufacturers have a diagnostic program for fan testing that allows you
to force the fan to turn on or off.

You should be able to find thermal pads on E-Bay or from some computer
parts vendors.  Or use thermal paste (there are some laptops whose
construction is such that you MUST use thermal pads, but fortunately not
too many of them.  The issue is whether the geometry of the CPU &
heatsink is such that without the thickness of the pad, you won't get
enough heatsink to CPU pressure to adequately cool the CPU.).

Re: Q.3. ... I'm sure it's true, but all that you are saying is that
there are some unscrupulous parts dealers.  What else is new?  Most
vendors are honest in their description of what they are selling.

Ken Kocher wrote:
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