Coolmaster PSU Fan issues

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Model: Coolmaster RP-500-PCAR 500w PSU

Problem: PSU's internal fan cycles on/off. It turns several
revolutions then stops. The cycle repeats.

Is the PSU failing? It is only 4 months old.


Re: Coolmaster PSU Fan issues

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Doesn't sound particulaly normal.

Why not send Coolermaster an email or livechat with them since it's under

Jan Alter

Re: Coolmaster PSU Fan issues

On Wed, 17 Dec 2008 07:20:37 -0800 (PST), MarkF

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If it's under very light load, I'd wonder if the fan control
circuit isn't giving it enough juice to stay spinning.  Has
the configuration of the system it's powering, stayed the
same all this time?

I have both the 600W and 500W version of that model, the
600W has been powering a system for a little under a year
and the 500W is just sitting around as a spare.  Neither
have done what you describe although their fans seem a
little low quality, I lubed the one in the 600W before using
it and it still seems a little rough running, and runs at a
bit higher RPM than it seems it would need to since the
system load on it is only about 100W to 180W depending on
what the system's doing.

I picked them up nearly (or completely, I forget which at
the moment) free after rebate so I couldn't justify paying
to ship it off for repair if I had a spare 120mm fan lying
around that could be swapped in.

Another thing to try which will also void the warranty is to
open it up, noticing there should be a thermal sensor
strapped to the heatsink on the right.  If you slide that
thermal sensor closer to the middle of the heatsink and put
a blob of thermal compound on it, that should ramp up the
fan speed slightly in case the problem is as mentioned above
that a light load isn't causing enough power for continual

If all else fails and you've opened it anyway, you might as
well lube the fan (heavyweight oil, a couple drops) and
could see if applying 12V from an external source directly
to the leads causes it to work.  This suggestion is within
the limit that you're comfortable working inside an
_unplugged_ PSU and know your way around a multimeter,
soldering iron, etc.

Re: Coolmaster PSU Fan issues

MarkF;883094 Wrote:
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hey guys. i have the same problem.. and its also a cooler master 600w

and i have this for 1 and a half year now. then suddenly i noticed the

stopping then goin again (cycle). then after 3 weeks. my pc now is
turning off

randomly without warning. pls i need an advice if i should buy new psu?

Thanks guys :D

Re: Coolmaster PSU Fan issues

cdanniels wrote:
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The power supply could have a warranty. If you're within the warranty
period, they may repair it for you.

If you're outside the warranty, then that isn't an option.

Power supplies usually have a warranty sticker on them - if you open
the supply, it breaks the warranty sticker, and the warranty is void.
If you're outside the warranty period, then breaking that sticker
doesn't matter.

The PSU will not last forever, if the fan stops. The PSU will get hot.
The heat will reduce the operating lifetime of the PSU or cause it
to switch off when it gets too hot. (It's possible, depending on the
fan configuration of the computer case, that some cooling air is
forced through the PSU anyway. But that might be less cooling than
the power supply normally gets.)

If the fan itself is defective, and the fan is connectorized inside the
PSU, you could attempt to repair it yourself. If the circuit driving the
fan is defective, then placing a new fan in it may not be enough. The
fan may have an intelligent fan controller connected to it, and a
failure of that circuit may prevent even a new fan from working

Fans come in four speed grades. And have operating voltage ranges,
such as 7V to 12V or 5V to 12V. You have to carefully select a fan,
to do a proper replacement. The manufacturer may be using a lower
voltage to run the fan, and the wrong fan may not turn at all.

Sometimes, all the original fan needs is lubrication with oil. But
if lubrication helps, you may end up doing it again and again. And that
means taking the power supply out of the computer again and again.
Replacing the fan may increase the interval before it needs maintenance
again. A typical lifespan for a quality fan, is about 3 years of operation,
24 hours a day.

The printed circuit board of the PSU, has capacitors that are charged
to dangerous voltage when the supply is running. Bleeder resistors are
connected across the capacitors, to make them safe after the supply is
turned off. But if a bleeder resistor fails open circuit, the high
voltages may remain on the capacitor for long periods of time.
Never assume the bleeders are working, when repairing such things!

In this picture, C5 and C6 are charged to high voltage. R2 and R3
are the bleeder resistors, which drain the caps when the supply is
turned off. If R2 or R3 go open circuit (fail), C5 or C6 remain
dangerous when you're doing maintenance in there.

The fan may have a simple three pin connector, and plug to a pin
header on the PCB. It should be possible to change the fan, without
touching a lot of other stuff. If the fan is soldered to the PCB
(which would save a penny or two), at that point you as the
repairer, will be disassembling the power supply further, and
then there is more potential danger. Some supplies are actually
hard to take apart, due to the way they're assembled at the
factory. Always put back any insulating layers you find, while
working on it. The insulation is there for safety.

If you're a clumsy person, or don't understand the warning given above,
then stay out of there! I've only been thrown across my basement
floor by high voltage once, and once is enough! Even discharging
the main capacitors with a screwdriver is dangerous. Don't try that!
The noise can be so loud, as to be deafening. If you need to bleed
such things, use a bleeder resistor, followed by checking with a
multimeter rated for measurements of 1000V. Capacitors have
"bounce back" - bleeding them once, is not enough, The high
voltage comes back, and may require several bleeding attempts.
Using a bleeder resistor, is intended to avoid the deafening noise
that using a screwdriver blade would cause.

I've been made deaf for ten minutes, by the sound of the discharge
from a high voltage capacitor. This is *not* a joke. Capacitors are
not toys. If in doubt, work out how many joules are stored in
a high voltage capacitor, to get some idea how dangerous they are.
Use of a bleeder resistor, is intended to avoid the noise factor.
Some capacitors have enough energy stored in them, they can
damage your screwdriver (pit the tip). If the bleeder resistors
built into the PSU were always working, there would be no danger.
But if R2 or R3 fail, there is no warning that they are no longer
working. So it's a "potential danger", as in, most of the time
you're safe, unless you were not born lucky.


Re: Coolmaster PSU Fan issues

Paul wrote:
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I had a PC Power and Cooling power supply with the name Silencer 610
watts. It went belly up a week after the 2 year warranty was up. Now
it's trash.

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