Laptop fan question, what's the 3rd wire?

I need to replace the fan in my HP omni XE2. The generic ones I can
find have 3 wires and mine has only 2. What's the 3rd wire (RPM I
believe) and can I run the fan in the laptop OK if I cut it off? Or do
I need to connect it to one of the other wires?

JohnF

On Fri, 15 Aug 2003 18:28:41 GMT, mpi- (JohnF)
wrote:

>I need to replace the fan in my HP omni XE2. The generic ones I can
>find have 3 wires and mine has only 2. What's the 3rd wire (RPM I
>believe) and can I run the fan in the laptop OK if I cut it off? Or do
>I need to connect it to one of the other wires?
>
>JohnF

Just leave it open.

In article <>, says...
> Yes, the 3rd wire is the tachometer signal that lets the computer
> measure how fast the fan is turning. It's not necessary for operation
> of the fan, the fan doesn't care, it will run as long as it has power
> (the other two wires).
>
>
> JohnF wrote:
>
> > I need to replace the fan in my HP omni XE2. The generic ones I can
> > find have 3 wires and mine has only 2. What's the 3rd wire (RPM I
> > believe) and can I run the fan in the laptop OK if I cut it off? Or do
> > I need to connect it to one of the other wires?
> >
> > JohnF
>
>
I have tested this on multiple laptops. Interesting to note that on
many laptops, without that 3rd wire the fan will never turn on. Be very
careful if you use only a 2 wire fan, it may never activate.

JohnF wrote:
>
> I need to replace the fan in my HP omni XE2. The generic ones I can
> find have 3 wires and mine has only 2. What's the 3rd wire (RPM I
> believe) and can I run the fan in the laptop OK if I cut it off? Or do
> I need to connect it to one of the other wires?
>
> JohnF

I have a more basic question? How do you get the laptop open? I have
an HP Pavilion that I also need to replace the fan, but I'm not sure how
to get it open.

--
Bob Lipman
http://cic.nist.gov/lipman/

There's a lot of screws. You might try going to HP to find a schematic.
when you go to support, look for manuals, views, etc.

Just had to look one up for a Compaq and that was the easiest way to take it
apart.

There are usually screws on the bottom of the laptop and some are hidden.
Be very careful
as you don't want to damage anything. Especially around the keyboard. The
keys are very
easy to break or 'pop' off and a pain getting back on sometimes.



"Robert Lipman" <> wrote in message
news:...
> JohnF wrote:
> >
> > I need to replace the fan in my HP omni XE2. The generic ones I can
> > find have 3 wires and mine has only 2. What's the 3rd wire (RPM I
> > believe) and can I run the fan in the laptop OK if I cut it off? Or do
> > I need to connect it to one of the other wires?
> >
> > JohnF
>
> I have a more basic question? How do you get the laptop open? I have
> an HP Pavilion that I also need to replace the fan, but I'm not sure how
> to get it open.
>
> --
> Bob Lipman
> http://cic.nist.gov/lipman/
>