Help with Cooling Fan (Question)

Yes, power supply fans can be replaced but there is an important
caveat: a power supply can kill you

You have to love it when you're told, "Sure you can do it, but it
might kill you." I guess this is another reason to build your
own computer. Usually you'll have around a 2-3 year warranty on the
PSU, so if it goes and it's not under warrantee, you might as well
get a new one. Three years after you build your computer, you'll be
able to buy a power supply that will power it rather easily for
probably around $50 or less. Three years ago a 350w PSU was all you
needed for just about anything. Today, good 350w PSUs are rather
cheap.

On Fri, 13 Jan 2006 15:19:39 GMT, kony wrote:

I have systems
that don' exhibit fan noise at 65F but I have heard fans get
noisier when colder.

It was an old cheap PSU.

I suspect you need a new fan if the temp wasnt' much lower
than 65F.

Yep.

You live in TX though, yes?

Houston.

Recalling
pictures sent from relatives near Austin, it's a kodak
moment when it's even cold enough for snow to settle

It snows in the Panhandle.

that's not very cold.

It gets colder than 65F.


--

Violence Against Women and Department of Justice Reauthorization Act:

"Whoever...utilizes any device or software that can be used to
originate telecommunications or other types of communications that are
transmitted, in whole or in part, by the Internet... without
disclosing his identity and with intent to annoy, abuse, threaten, or
harass any person...who receives the communications...shall be fined
under title 18 or imprisoned not more than two years, or both."

On Fri, 13 Jan 2006 15:30:22 GMT, lid
(professor) wrote:

Yes, power supply fans can be replaced but there is an important
caveat: a power supply can kill you

You have to love it when you're told, "Sure you can do it, but it
might kill you." I guess this is another reason to build your
own computer.

Except that it won't. ATX power supplies do not retain a
lethal charge after unplugged. You'd have to have the
casing already off, power plugged in or be unplugging it
while challenging yoruself to touch something as quickly as
possible during a few seconds there's any HV remaining.

Except that it won't. ATX power supplies do not retain a
lethal charge after unplugged. You'd have to have the
casing already off, power plugged in or be unplugging it
while challenging yoruself to touch something as quickly as
possible during a few seconds there's any HV remaining.


Never underestimate the lethal power of human stupidity. If people
can find a way to install a memory module backwards, they can find a
way to kill themselves with a PSU.

On Fri, 13 Jan 2006 22:30:18 GMT, lid
(professor) wrote:

Except that it won't. ATX power supplies do not retain a
lethal charge after unplugged. You'd have to have the
casing already off, power plugged in or be unplugging it
while challenging yoruself to touch something as quickly as
possible during a few seconds there's any HV remaining.


Never underestimate the lethal power of human stupidity. If people
can find a way to install a memory module backwards, they can find a
way to kill themselves with a PSU.


Has nothing to do with stupidity, only recognizing what
plugged vs unplugged for a few seconds means.

kony wrote:

Yes, power supply fans can be replaced but there is an important
caveat: a power supply can kill you

You have to love it when you're told, "Sure you can do it, but it
might kill you." I guess this is another reason to build your
own computer.

Except that it won't. ATX power supplies do not retain a
lethal charge after unplugged. You'd have to have the
casing already off, power plugged in or be unplugging it
while challenging yoruself to touch something as quickly as
possible during a few seconds there's any HV remaining.

ATX supplies are no different from AT supplies when it comes to
the discharge rate of the 300v buss. It varies with design. I
always kept a 47K bleed resistor handy when playing with _any_
SMPS, AT or ATX.

On Fri, 13 Jan 2006 15:54:52 -0800, UCLAN
wrote:

kony wrote:

Yes, power supply fans can be replaced but there is an important
caveat: a power supply can kill you

You have to love it when you're told, "Sure you can do it, but it
might kill you." I guess this is another reason to build your
own computer.

Except that it won't. ATX power supplies do not retain a
lethal charge after unplugged. You'd have to have the
casing already off, power plugged in or be unplugging it
while challenging yoruself to touch something as quickly as
possible during a few seconds there's any HV remaining.

ATX supplies are no different from AT supplies when it comes to
the discharge rate of the 300v buss. It varies with design. I
always kept a 47K bleed resistor handy when playing with _any_
SMPS, AT or ATX.

Yes they are different! Surely I dont need to tell you why?
Hint: 5VSB

Again I ask for an example, show one power supply that is
ATX that does not self-discharge the caps. AFAIK, there is
not one. When you used that 47K bleed resistor, did you
actually meaure the voltage first? Part of the typical
manual-voltage selection type PSU is also a stabilization
gained by the resistors across the voltage doubling
subcircuit.

It doesn't vary by design unless you're talking about
something else as one design and an ATX power supply as the
other design.

kony wrote:

ATX supplies are no different from AT supplies when it comes to
the discharge rate of the 300v buss. It varies with design. I
always kept a 47K bleed resistor handy when playing with _any_
SMPS, AT or ATX.

Yes they are different! Surely I dont need to tell you why?
Hint: 5VSB

Again I ask for an example, show one power supply that is
ATX that does not self-discharge the caps. AFAIK, there is
not one. When you used that 47K bleed resistor, did you
actually meaure the voltage first? Part of the typical
manual-voltage selection type PSU is also a stabilization
gained by the resistors across the voltage doubling
subcircuit.

It doesn't vary by design unless you're talking about
something else as one design and an ATX power supply as the
other design.

Not all ATX PSU designs have +5vsb circuits that run off the
300v buss. Many early designs used a small bias type transformer
to provide the input for the +5vsb. As +5vsb current requirements
increased, more and more +5vsb designs went to a switching output
fed by the 300v buss. That's why I said it depends on the design.
And even in those PSUs where the +5vsb _is_ fed by the 300v, a
failure in that circuit *will* slow discharge rate.

As far as resistors across the 300v buss go, I would love to hear
explain why they are different/lower value in ATX type supplies.

On Fri, 13 Jan 2006 22:21:08 -0800, UCLAN
wrote:

kony wrote:

ATX supplies are no different from AT supplies when it comes to
the discharge rate of the 300v buss. It varies with design. I
always kept a 47K bleed resistor handy when playing with _any_
SMPS, AT or ATX.

Yes they are different! Surely I dont need to tell you why?
Hint: 5VSB

Again I ask for an example, show one power supply that is
ATX that does not self-discharge the caps. AFAIK, there is
not one. When you used that 47K bleed resistor, did you
actually meaure the voltage first? Part of the typical
manual-voltage selection type PSU is also a stabilization
gained by the resistors across the voltage doubling
subcircuit.

It doesn't vary by design unless you're talking about
something else as one design and an ATX power supply as the
other design.

Not all ATX PSU designs have +5vsb circuits that run off the
300v buss. Many early designs used a small bias type transformer
to provide the input for the +5vsb.

So where are you claiming this transformer input is
filtered? The issue is not whether there was a separate
transformer as that is quite common today.

As +5vsb current requirements
increased, more and more +5vsb designs went to a switching output
fed by the 300v buss.

No, that was by far the most common arrangement since day 1
of ATX.

That's why I said it depends on the design.
And even in those PSUs where the +5vsb _is_ fed by the 300v, a
failure in that circuit *will* slow discharge rate.

"Slow" in context, nobody suggested a race to see if you can
unplug the AC power cord with one hand while simultaneously
lunging at the HV parts with the other to see if you can
manage to touch them before caps have drained. Rather,
unplugging the supply before it's opened is sufficient.



As far as resistors across the 300v buss go, I would love to hear
explain why they are different/lower value in ATX type supplies.

Who claimed they're different/lower values? Not I.

Has nothing to do with stupidity, only recognizing what
plugged vs unplugged for a few seconds means.

In my old A+ class, I watched someone use a hammer to insert a socket
A CPU. I do not mean using the back of the hammer like a screwdriver
to push the heatsink’s connectors; I mean actually hammering the thing
into place, or at least trying to. You want to know what "step
1" was for him in the assembly phase? Plug the power supply in.
Trust me, there are people out there dumb enough to leave a PSU
plugged in while opening it up. Then they may proceed to hit it with
a hammer...