Computer Fan

[amdx]

The case fan in my computer was running slow. The computer is running hot.
The original fan has three wires, I replaced it with a two wire fan and all
is well.
However I wonder what the third wire is for. The fan is 12v dc powered.
Mike

 

[Tim Harig]

On 2009-06-11, amdx <amdx@knology.net> wrote:

The case fan in my computer was running slow. The computer is running hot.
The original fan has three wires, I replaced it with a two wire fan and all
is well.
However I wonder what the third wire is for. The fan is 12v dc powered.

The third wire is for speed control and monitoring. It allows the
motherboard to vary the speed of the fan based on the systems heat.

 

[amdx]

"Tim Harig" <usernet@ilthio.net> wrote in message
news:8daYl.19583$pr6.4899@flpi149.ffdc.sbc.com...

On 2009-06-11, amdx <amdx@knology.net> wrote:
The case fan in my computer was running slow. The computer is running
hot.
The original fan has three wires, I replaced it with a two wire fan and
all
is well.
However I wonder what the third wire is for. The fan is 12v dc powered.

The third wire is for speed control and monitoring. It allows the
motherboard to vary the speed of the fan based on the systems heat.

That's what I thought, now I wonder if the motor is the problem causing
the low speed or
if the speed control (mobo) is the problem.
Mike
PS. I had three leaky capacitors near the CPU, I replaced 7 caps around the
CPU and got the computer
working. I suspect the fan has been slow for a while and the caps
overheated.

 

[Rich Webb]

On Thu, 11 Jun 2009 10:40:32 -0500, "amdx" <amdx@knology.net> wrote:

The case fan in my computer was running slow. The computer is running hot.
The original fan has three wires, I replaced it with a two wire fan and all
is well.
However I wonder what the third wire is for. The fan is 12v dc powered.

1 = GND/control
2 = +12
3 = tach pulse
4 = PWM

3 and 4 are optional, although 4-wire systems may not be happy if the
tach line isn't present.

If your system supports it, the tach line can be read back through the
(usually) SMBus and thus alert you if the fan fails.

Of course, as always, nothing prevents a mobo or fan manufacturer from
using a non-standard pinout but the above is what pretty much all are
using nowadays.

--
Rich Webb Norfolk, VA

 

[Baron]

amdx wrote:

"Tim Harig" <usernet@ilthio.net> wrote in message
news:8daYl.19583$pr6.4899@flpi149.ffdc.sbc.com...
On 2009-06-11, amdx <amdx@knology.net> wrote:
The case fan in my computer was running slow. The computer is
running hot.
The original fan has three wires, I replaced it with a two wire fan
and
all
is well.
However I wonder what the third wire is for. The fan is 12v dc
powered.

The third wire is for speed control and monitoring. It allows the
motherboard to vary the speed of the fan based on the systems heat.

That's what I thought, now I wonder if the motor is the problem
causing the low speed or if the speed control (mobo) is the problem.
Mike
PS. I had three leaky capacitors near the CPU, I replaced 7 caps
around the CPU and got the computer
working. I suspect the fan has been slow for a while and the caps
overheated.

That easy enough to prove ! Just disconnect the yellow wire. The fan
will now try to run at full speed. If its still slow then its faulty !

--
Best Regards:
Baron.

 

[Lord Garth]

"amdx" <amdx@knology.net> wrote in message
news:d8fc2$4a314955$d8baf3ed$19604@KNOLOGY.NET...

"Tim Harig" <usernet@ilthio.net> wrote in message
news:8daYl.19583$pr6.4899@flpi149.ffdc.sbc.com...
On 2009-06-11, amdx <amdx@knology.net> wrote:
The case fan in my computer was running slow. The computer is running
hot.
The original fan has three wires, I replaced it with a two wire fan and
all
is well.
However I wonder what the third wire is for. The fan is 12v dc powered.

The third wire is for speed control and monitoring. It allows the
motherboard to vary the speed of the fan based on the systems heat.

That's what I thought, now I wonder if the motor is the problem causing
the low speed or
if the speed control (mobo) is the problem.
Mike

It is often possible to clean and lubricate fans but it takes some work to
remove the split washer that holds the motor shaft in place. Remove the
fan label and the access cover that is hidden underneath the label.
Immobilize
the fan frame and look for the thin line in the washer. Using a small tool,
carefully remove the washer taking care that it doesn't fly off to unseen
places.
These washers can also be brittle so be careful not to crack it into pieces.

Remove the shaft from the sleeve bearing or bearing chase and clean the
shaft
as well as the sleeve or chase. Re-lubricate using a light machine oil for
a chase
or a light grease for a sleeve bearing. Reassemble the parts.

The fan blades should rock clockwise and anti-clockwise when spun manually.

I've had some of these repairs add over three years to a fans life span.

 

[Tom Biasi]

"amdx" <amdx@knology.net> wrote in message
news:d8fc2$4a314955$d8baf3ed$19604@KNOLOGY.NET...

"Tim Harig" <usernet@ilthio.net> wrote in message

Mike
PS. I had three leaky capacitors near the CPU, I replaced 7 caps around
the CPU and got the computer
working. I suspect the fan has been slow for a while and the caps
overheated.

Unlikely that the caps failed due to overheating. Replacing componentents on

a MB is very risky. There are several layers between top and bottom, and its
easy to screw up an internal layer.

Tom

 

[z]

On Jun 11, 10:27 pm, "Tom Biasi" <tombi...@optonline.net> wrote:

"amdx" <a...@knology.net> wrote in message

news:d8fc2$4a314955$d8baf3ed$19604@KNOLOGY.NET...



"Tim Harig" <user...@ilthio.net> wrote in message
                           Mike
PS. I had three leaky capacitors near the CPU, I replaced 7 caps around
the CPU and got the computer
working. I suspect the fan has been slow for a while and the caps
overheated.

Unlikely that the caps failed due to overheating. Replacing componentents on
a MB is very risky. There are several layers between top and bottom, and its
easy to screw up an internal layer.

Tom

best approach is to stay away from the board; munch the component up
with a pair of pliers until just the leads are left sticking out of
the board, then solder the new component to them.

 

[Greegor]

On Jun 11, 10:37 pm, z <gzuck...@snail-mail.net> wrote:

best approach is to stay away from the board; munch the component up
with a pair of pliers until just the leads are left sticking out of
the board, then solder the new component to them.

Sounds like it would be good electically but ugly to look at.

Are there any photos of what this looks like on the web?

 

[amdx]

"Tom Biasi" <tombiasi@optonline.net> wrote in message
news:4a31bd07$0$31266$607ed4bc@cv.net...

"amdx" <amdx@knology.net> wrote in message
news:d8fc2$4a314955$d8baf3ed$19604@KNOLOGY.NET...

"Tim Harig" <usernet@ilthio.net> wrote in message

Mike
PS. I had three leaky capacitors near the CPU, I replaced 7 caps around
the CPU and got the computer
working. I suspect the fan has been slow for a while and the caps
overheated.

Unlikely that the caps failed due to overheating.

I don't know for sure, the caps are right next to the cpu heatsink, the bad
fan is ducted to
move air past these caps. The HP computer is about 5 years old.
The old caps were Rubycon brand, replaced with same.

Replacing componentents on a MB is very risky. There are several layers
between top and bottom, and its easy to screw up an internal layer.
Tom

Maybe risky, but I had nothing to lose.
I could have sent it to a pro and had caps replaced for about $75.00 or buy
a new
(different brand) board for about $60.00. I would have had to get drivers
if I
bought a new board. Sooo, If the board didn't work after I replaced the caps
I would
have bought a new mobo. The cap seller sent me 7 caps at no charge ( I don't
know why)
but I did send him $10.00 just cause he was so nice!
It has been running 4 days continuously without a glitch, I think it's
repaired.

A little history about the computer, I bought it used at 2 yrs old. Within
3 months I noticed
a burning smell, I shut it down and opened it up. I found the power supply
had a burned up
power thermistor ( http://www.amwei.com/views.asp?hw_id=64 ) and carbonized
area on the pcb.
I cleaned up the board and installed a new thermistor. At the same time I
found the power supply fan
had a dead spot, if stopped on that spot it wouldn't restart. The
manufacturer sent me a pulled fan,
and I installed that. Now a couple years later I have the leaky caps causing
lockup problems.
Don't know if this is common for HP computers, but I don't have a good
feeling about them now.
Ya, I know, a 5 year old computer is ancient. Hmm, I still have a
10yr old Abit KT7A 700Mhz
PC running 24/7 without any problems. I just realized I still have a Compaq
100Mhz computer that is
about 15yrs old, I think it's trash now, cause I stole the fan out of the
Compaq for the HP. Maybe
now I can part with it.
Mike

 

[amdx]

"Tim Harig" <user...@ilthio.net> wrote in message
Mike
PS. I had three leaky capacitors near the CPU, I replaced 7 caps around
the CPU and got the computer
working. I suspect the fan has been slow for a while and the caps
overheated.

Unlikely that the caps failed due to overheating. Replacing componentents
on
a MB is very risky. There are several layers between top and bottom, and
its
easy to screw up an internal layer.

Tom

best approach is to stay away from the board; munch the component up
with a pair of pliers until just the leads are left sticking out of
the board, then solder the new component to them.

I cranked up the variable temp iron as high as it would go. Then made sure
there
was a little solder on the tip for good heat transfer, then applied heat to
the joint until
I could lift one side of the cap. I did the same for the other lead and then
repeated until
the cap was free. The caps did not come out easy, I started with a non
variable temp
Weller iron but that didn't seem to get it hot enough move the leads.
I had to borrow a variable temp iron to get a little more heat.
Once I had the caps out I used a stainless needle and the soldering iron to
clean the solder
out of the holes and allow the new cap leads to fit. Hmm, never used any
solderwick or a solder sucker.
The computer works fine now.
Mike

 

[Baron]

amdx wrote:

"Tim Harig" <user...@ilthio.net> wrote in message
Mike
PS. I had three leaky capacitors near the CPU, I replaced 7 caps
around the CPU and got the computer
working. I suspect the fan has been slow for a while and the caps
overheated.

Unlikely that the caps failed due to overheating. Replacing
componentents on
a MB is very risky. There are several layers between top and bottom,
and its
easy to screw up an internal layer.

Tom

best approach is to stay away from the board; munch the component up
with a pair of pliers until just the leads are left sticking out of
the board, then solder the new component to them.

I cranked up the variable temp iron as high as it would go. Then made
sure
there
was a little solder on the tip for good heat transfer, then applied
heat to the joint until
I could lift one side of the cap. I did the same for the other lead
and then repeated until
the cap was free. The caps did not come out easy, I started with a non
variable temp
Weller iron but that didn't seem to get it hot enough move the leads.
I had to borrow a variable temp iron to get a little more heat.
Once I had the caps out I used a stainless needle and the soldering
iron to clean the solder
out of the holes and allow the new cap leads to fit. Hmm, never used
any solderwick or a solder sucker.
The computer works fine now.
Mike

A hot air paint stripper is handy for preheating the mainboard before
you try to remove the caps. It makes it easier on the soldering iron.

--
Best Regards:
Baron.