PSU Fan issue

[GreY2231]

Hello and good day. I have a Cougar CMX 550w. The PSU starts up but the fan does not spin. When I test the fan with a 12v bench supply it spins up fine. Is this normal? I thought it would at least spin up at start and then slow down and adjust for load. Thanks in advance for any help.

[Entropy.]

5 minutes ago, GreY2231 said:

Hello and good day. I have a Cougar CMX 550w. The PSU starts up but the fan does not spin. When I test the fan with a 12v bench supply it spins up fine. Is this normal? I thought it would at least spin up at start and then slow down and adjust for load. Thanks in advance for any help.

PSU's also have fan curves. Usually they start out silent until they HAVE to start up to cool the unit. Should be totally fine, stress-testing yoru components requires more power obviously, which requires the PSU to pump out more watts, and it eventually reaches the point where the fan HAS to be turned on.

[TheGlenlivet]

5 minutes ago, GreY2231 said:

Hello and good day. I have a Cougar CMX 550w. The PSU starts up but the fan does not spin. When I test the fan with a 12v bench supply it spins up fine. Is this normal? I thought it would at least spin up at start and then slow down and adjust for load. Thanks in advance for any help.

Fan might be going bad?  I don't see that the PSU has a zero RPM mode, at least not in any review I could find.

[Boomwebsearch]

28 minutes ago, GreY2231 said:

Hello and good day. I have a Cougar CMX 550w. The PSU starts up but the fan does not spin. When I test the fan with a 12v bench supply it spins up fine. Is this normal? I thought it would at least spin up at start and then slow down and adjust for load. Thanks in advance for any help.

 

I wouldn't recommend opening and tinkering with or attempting repairs on a power supply unless you are an electrician and are aware of the associated risks, there are high-voltage capacitors which can hold high amounts of charge for long after unplugged. Could be a control circuit on the power supply that went bad or something along those lines, better to just replace the PSU or file a warranty claim if possible.

[GreY2231]

3 minutes ago, Boomwebsearch said:

 

I wouldn't recommend opening and tinkering with or attempting repairs on a power supply unless you are an electrician and are aware of the associated risks, there are high-voltage capacitors which can hold high amounts of charge for long after unplugged. Could be a control circuit on the power supply that went bad or something along those lines, better to just replace the PSU or file a warranty claim if possible.

I am exactly that. I have nearly 20 years Experience 110v, 230v and 12/24v systems. But thank you for being concerned. 

[GreY2231]

Just to be safe I installed a 3 pin 140mm fan and will attach it to a MB Header. Better safe than sorry. Afaik they have a low noise mode but not Zero RPM.

[Boomwebsearch]

11 minutes ago, GreY2231 said:

Just to be safe I installed a 3 pin 140mm fan and will attach it to a MB Header. Better safe than sorry. Afaik they have a low noise mode but not Zero RPM.

 

That's probably fine, if you have a thermal camera, may want to check the temperatures of the PSU, a good PSU should automatically shutdown in the case of an overheat, short, etc, although better to have a fan than not.

[Guest]

39 minutes ago, GreY2231 said:

Just to be safe I installed a 3 pin 140mm fan and will attach it to a MB Header. Better safe than sorry. Afaik they have a low noise mode but not Zero RPM.

This is not a good idea because MB header isn't going to respond to higher temperatures within the PSU.   If it's hot inside the PSU, but not where the fan header is getting it's temps read from, the fan in the PSU will not spin up enough to cool the PSU.

 

And you're correct:  The Cougar CMX does not have a "zero RPM fan mode".  But it is a DC fan.  My guess is your PSU's < 12V output is below optimal, causing the lowest voltage output of the fan controller to be below the start up voltage of the fan.

[GreY2231]

4 hours ago, jonnyGURU said:

This is not a good idea because MB header isn't going to respond to higher temperatures within the PSU.   If it's hot inside the PSU, but not where the fan header is getting it's temps read from, the fan in the PSU will not spin up enough to cool the PSU.

 

And you're correct:  The Cougar CMX does not have a "zero RPM fan mode".  But it is a DC fan.  My guess is your PSU's < 12V output is below optimal, causing the lowest voltage output of the fan controller to be below the start up voltage of the fan.

The header it is plugged into is not a temp regulated one. It's just, on. And when the original fan is in, it doesn't spin at all. I didn't check output voltages yet. I decided to use another PSU until I knew it was ok and safe.