Power Supply - DOA?

  • Thread starter Thread starter endorice
  • Start date Start date
E

endorice

I'm putting an Asus P4P800-SE motherboard in an Antec SLK2650-BQE that
has an Antec SP-350 SmartPower power supply.

When I turned on the machine, the power supply fan doesn't come on.
I
get screen display, and make it into the BIOS setup and then the
system
just shuts off. In the BIOS screen, I see that my CPU and drive have
been detected.

I do have the green LED "stand-by" illuminated on the motherboard. I
have connected the PWR_FAN from the motherboard connected to the leads
from the power supply. I do not yet have a CPU fan installed (thought
I'd do that after the system boots properly).

Can I safely assume that the power supply is bad, or are there other
things I should be checking for?

Any help would be *greatly* appreciated!
 
Some mobo's have a safety mechanism that prevents the mobo from booting if
the CPU fan is not functional! It's intended to save your CPU. So there's
really no reason not to hook it up. It may also shutdown the mobo if the
fan runs too slowly.

Jim
 
Some mobo's have a safety mechanism that prevents the mobo from booting if
the CPU fan is not functional! It's intended to save your CPU. So there's
really no reason not to hook it up. It may also shutdown the mobo if the
fan runs too slowly.
Click to expand...

There is a very good reason not to hook it up- if the fan
doesn't have RPM feedback or it's not supposed to spin fast
and the board isn't calibrated properly for low fan RPMs
(it's VERY common that boards aren't).

Providing the CPU thermal sensing is working properly there
is no real need for a fan failure shutdown, and in fact it
is extremely rare to see a fan failure with a good quality
large fan running at low RPM.
 
I'm putting an Asus P4P800-SE motherboard in an Antec SLK2650-BQE that
has an Antec SP-350 SmartPower power supply.

When I turned on the machine, the power supply fan doesn't come on.
I
get screen display, and make it into the BIOS setup and then the
system
just shuts off.
Click to expand...

Next time, don't go into the bios setup "yet". Watch the
initial POST screen to see if it shows any alerts for
something like a fan failure notice.

Either way, check the bios for that setting and (at least
temporarily) disable it, as well as disabling any other
similar shutdown alerts.

However, before you do that, make sure your heatsink is
installed properly. If the CPU is overheating it can do
exactly as you report, and turning off a shutdown mechanism
for CPU overheat when it IS overheating could damage it. To
be on the safe side I suggest that you remove the heatsink,
examine the base to see if it looked like it was making good
contact. However, if you do that you may not be able to
reuse the original thermal pad or compound, may need clean
off the original and apply fresh compound. If it is
difficult to clean off, try a petroleum based solvent if
alcohol won't dissolve it.
In the BIOS screen, I see that my CPU and drive have
been detected.

I do have the green LED "stand-by" illuminated on the motherboard. I
have connected the PWR_FAN from the motherboard connected to the leads
from the power supply.
Click to expand...

Disconnect that - do this first and then retry the system.
I do not yet have a CPU fan installed (thought
I'd do that after the system boots properly).
Click to expand...

What are you thinking here?
You should never have turned on the system without the fan.
It is not subject to your desires whether to do this. It
requires fan cooling, period. It can run for a few dozen
seconds before it begins to get to a point of overheating,
but cycling it on and off does not "reset" that few dozen
seconds unless you allow the 'sink to completely cool
inbetween each. Certainly booting the system and the
resulting state is going to be more than a few dozen
seconds, there was no good reason not to install the fan
already.

Can I safely assume that the power supply is bad, or are there other
things I should be checking for?
Click to expand...

No, there is no reason to suspect the power supply is bad
until after you take voltage readings with a multimeter, and
then if the voltages look out of spec. It is premature to
conclude and not a primary suspect yet.
 
kony said:
There is a very good reason not to hook it up- if the fan
doesn't have RPM feedback or it's not supposed to spin fast
and the board isn't calibrated properly for low fan RPMs
(it's VERY common that boards aren't).
Click to expand...

If you install *some* CPUs without a fan, you'll KILL the CPU in seconds!
The AMD Athlon was/is notorious for this, so much so the manfacturer voids
the warranty if you fail to do so. The probability that the fan isn't
calibrated correctly seems remote, to me. And so what if it is, the fact
remains you typically want (if not need) a running fan. The fact it may or
may not be running "to spec" is moot. The issue here is, there's no good
reason to not have the CPU fan running, and a darn good chance if you don't,
you'll damage the CPU.

Jim
 
You connected power to the power_fan connector on the motherboard?
Good luck with the next board you buy!!
 
If you install *some* CPUs without a fan, you'll KILL the CPU in seconds!
Click to expand...

No, you might mean without the heatsink itself though.
Leaving only the fan off, the CPU will not die "in seconds".
In a few dozen seconds the system will have a CPU overheat
event and shut off, or the CPU will become instable and
crash. That does not mean I suggest allowing this to
happen, only that the timeframe is a bit less crucial so
long as the (metal) heatsink itself is correctly installed.

The AMD Athlon was/is notorious for this, so much so the manfacturer voids
the warranty if you fail to do so. The probability that the fan isn't
calibrated correctly seems remote, to me.
Click to expand...

Whether it seems remote to you or not does not change the
reality of the situation. It's a fact that a VERY large %
of boards do not register low RPM fans properly, though many
do eventually have bios updates that address this issue.
And so what if it is, the fact
remains you typically want (if not need) a running fan.
Agreed.

The fact it may or
may not be running "to spec" is moot. The issue here is, there's no good
reason to not have the CPU fan running, and a darn good chance if you don't,
you'll damage the CPU.
Click to expand...

Never wrote otherwise, reread what I wrote.
 
If you install *some* CPUs without a fan, you'll KILL the CPU in seconds!
The AMD Athlon was/is notorious for this, so much so the manfacturer voids
the warranty if you fail to do so.
Click to expand...


Maybe without a fan AND heatsink, yes. With a heatsink the system would last
at least a minute, even with the hot-headed Thunderbird. So there is no way
that the CPU is getting too hot in the 5-10 seconds before post. Also, if
the MB was powering the system down due to thermal or fan failure you would
get some type of beep code or BIOS message.


For the OP - If the PS fan doesn't spin up when you turn the system on it's
defective, return it.
--


"I don't cheat to survive. I cheat to LIVE!!"
- Alceryes
 
For the OP - If the PS fan doesn't spin up when you turn the system on it's
defective, return it.
Click to expand...

Some Antecs have a fan control and noise reduction feature
that does allow fan to not spin until it gets hotter. It
can matter if it's plugged into a motherboard PSU fan header
(or another fan header) or not.
 
Some Antecs have a fan control and noise reduction feature
that does allow fan to not spin until it gets hotter. It
Click to expand...


Yes, but I think these power supply fans at least spin up when first powered
on and then stop once the thermistor reading kicks in. That way if you have
a failure at least you have the fan running instead of stopping (and most
likely taking the PS with it).
 
Thanks to everyone who contributed suggestions for me, much
appreciated!
Some mobo's have a safety mechanism that prevents the mobo from
Click to expand...
booting if the CPU fan is not functional! It's intended to save your
CPU. So there's
really no reason not to hook it up. It may also shutdown the mobo if the
fan runs too slowly.
Click to expand...
Well, that's exactly what the problem was. I was transferring this
CPU from a Dell 4600, which had a heat sink, but no CPU fan. I
thought I could boot the machine, confirm everything was working OK
(run for a minute) and then I was going to hook up the CPU fan.
Turns out that this Asus motherboard required the CPU fan to be
hooked up before booting (althought it's not specifically mentioned
in the manual).
You connected power to the power_fan connector on the motherboard?
Click to expand...
Good luck with the next board you buy!!
OK - I don't follow. My motherboard has a 3 pin PWR_FAN connector. I
*assumed* I was supposed to take the female connector that came out of
the power supply, and hook to the male connector on the MB. Am I
wrong about that?

Anyhow, I just hooked up the CPU fan, and now I'm booting into safe
mode and running windows. I have a couple of BIOS warnings about
overclock settings not being correct which I'll look at later.

Thanks again for all of your suggestions!
 
Back
Top