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New PSU - Case fans remain lit after PC shutdown


AdzUK

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Hi all, new member here, just signed up to see if anyone can offer any advice. :)

 

I've just replaced my trustly old 700W OCZ power supply with a Corsair RM1000 with the thought I may go SLI down the line. Anyway, that's the only thing that has been changed in my system.

 

Previously, when I would shut down my PC, the led on the front of the fan controller would remain lit. I've installed the RM1000 and it seems to be working great however, after shutting down the system, all my case fans (6 of them) remain lit although they are quite dim. They are not spinning, the system has definitely shut down but the leds are still on and this seems and looks a bit odd to me. Is it normal?

 

What I've tried so far:

 

I shutdown my PC and switched OFF the PSU from the switch at the back of the tower/PSU. The fan led lights remain ON. After 5 minutes of waiting, the fan lights are still ON. I've opened the case and tried different ports on the PSU and when I unplug the cable from PSU, the fan lights go off, but as soon as I plug it back into the PSU (tried all the ports) the fan lights come back ON. This is all while the PSU is switched OFF from the back.

 

As I said, the PSU seems to be working fine. Just wondering if the above is something I should be concerned about?

 

Another thing is, I know that the PSU fan doesn't spin unless at around 40% load. I've played games and tried benchmarks and it doesn't spin at all. I've just ran prime 95 and furmark together which stressed the CPU and GPU massively sending GPU temps up to over 80C and CPU temps to over 60C and after around 5 minutes my system crashed. It's never crashed before but at no point did the PSU fan even move. Is this normal?

Edited by AdzUK
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  • Corsair Employee

First off, you're using a 1000W PSU with only one graphics card. If you fire up Link (since that PSU actually came with the Link dongle) and look at your +12V load, I bet it's probably under 400W. So I doubt that fan will ever turn on.

 

As for the fans: What are the fans plugged into? The fan controller? The motherboard? Directly into the PSU? I don't think that part was made clear.

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Hi there.

 

My case has 6 led fans and they are all plugged into the fan controller. The fan controller is powered by the psu via molex cable.

 

When I remove that cable from the psu the fan lights go off. If I just switch the psu off from the back and even remove the power lead, the case fans remain lit.

 

Im just going bed now and I've shutdown the pc, and also switched off the psu from the back. Will see in the morning if the fans are still lit, I can't understand where they are getting power from?

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  • Corsair Employee

They won't be. Eventually the capacitors will drain.

 

Capacitors, by their very nature, store energy. See, your 700W had capacitors only large enough to keep the fan controller lit up for a while. This 1000W has enough capacitance to keep the fan controller AND the fans lit up for quite some time.

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They won't be. Eventually the capacitors will drain.

 

Capacitors, by their very nature, store energy. See, your 700W had capacitors only large enough to keep the fan controller lit up for a while. This 1000W has enough capacitance to keep the fan controller AND the fans lit up for quite some time.

 

are you sure you know what you are talking about, because this sounds like a load of nonsense...

 

 

 

it sounds like a dodgy psu, a quick google shows others reporting similar, see here also:

 

http://www.techrepublic.com/forums/questions/case-fans-hard-drive-led-light-on-after-shutdown/#.

 

http://answers.microsoft.com/en-us/windows/forum/windows_xp-performance/fans-and-leds-stay-on-after-shutdown/59253d5b-cdea-4c7f-bc1e-5d237c12520e

 

 

 

it's a dodgy psu...

 

is your hdd light still on? (assuming you plugged the led connectors the right way round on the motherboard :p)

Edited by Azh
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Just got home from work, its 4.45pm and I can confirm the fan led lights are... STILL ON!

 

This is despite me switching the PSU off from the switch at the back ~17 hours ago. If my fans didn't have any leds I wouldn't even have known there was an issue? Can someone please advise whether this is normal. I understand the capacitors have stored energy and the power obviously has to come from somewhere, but 17 hours later and they are still on???

 

Azh - thanks for those links I'm gonna read through them now.

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Have you tried taking the plug out of the socket?

 

Yes - well I unplugged the lead from the back of the PSU so same thing. The fan led lights remain on.

 

The only time the fan lights go off is when I unplug that molex cable which is plugged into the fan controller, from the PSU. If I remove that cable then the lights go off. Soon as I put it back in (I've tried all the ports on the PSU) the lights come back on.

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  • Corsair Employee
are you sure you know what you are talking about, because this sounds like a load of nonsense...

 

Thanks for the vote of confidence. ;):

 

Do you think DC power comes from thin air?

 

If I just switch the psu off from the back and even remove the power lead, the case fans remain lit.

 

If the lights stayed lit when the switch was turned off, but then went out when the plug was pulled, I would say faulty switch. Get an RMA.

 

But he's killing ALL AC power to the PSU by pulling the plug. Yet there's still DC power coming from the PSU. Why?

 

A larger capacity PSU has larger capacitors. The bulk cap is larger to maintain a specified hold up time if there's a brown out and there are more and larger capacity secondary capacitors to filter out ripple even at higher loads.

 

The fan controller probably uses FETs instead of resistors to control the voltage to the fans, which is way more efficient, but can still leak through a little bit of juice to the fans causing the LEDs to shine just a little bit and yet never fully drain the capacitors in the PSU.

 

I bet if you plug the fans directly into the PSU without the fan controller, those fans would only stay lit up for a second because it's a more resistive load than the fan controller.

Edited by jonnyguru
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I don't think it is the switch jonnyguru

they would go off when he unplugged the lead from the back of the psu?

 

Yes - well I unplugged the lead from the back of the PSU so same thing. The fan led lights remain on.

 

The only time the fan lights go off is when I unplug that molex cable which is plugged into the fan controller, from the PSU. If I remove that cable then the lights go off. Soon as I put it back in (I've tried all the ports on the PSU) the lights come back on.

Edited by Technobeard
fixed the bbcode
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  • Corsair Employee
I don't think it is the switch jonnyguru

they would go off when he unplugged the lead from the back of the psu?

 

Yes - well I unplugged the lead from the back of the PSU so same thing. The fan led lights remain on.

 

The only time the fan lights go off is when I unplug that molex cable which is plugged into the fan controller, from the PSU. If I remove that cable then the lights go off. Soon as I put it back in (I've tried all the ports on the PSU) the lights come back on.

 

Yeah. That's why I did the edit. I thought I misread the post, thinking the plug was pulled and the lights went out. Then I re-read it and found that he pulled the plug and the lights stayed on.

 

So Azh apparently thinks Corsair has created a PSU with wireless power capabilities and that we're creating DC power out of thin air. ;):

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Yeah. That's why I did the edit. I thought I misread the post, thinking the plug was pulled and the lights went out. Then I re-read it and found that he pulled the plug and the lights stayed on.

 

So Azh apparently thinks Corsair has created a PSU with wireless power capabilities and that we're creating DC power out of thin air. ;):

 

I thought you were off your head, but now I know you are :roll:

 

See, your 700W had capacitors only large enough to keep the fan controller lit up for a while. This 1000W has enough capacitance to keep the fan controller AND the fans lit up for quite some time

 

read this dribble you posted and try not to laugh at the same time :D:

 

 

I'm bringing some popcorn, :D maybe you'll bring some sensible suggestions to the table, I wont hold my breath though ;):

 

 

the OCZ 700w behaves normally, switches all devices off instantly when the system is shut down

the faulty Corsair 1000w keeps the fan leds on (god knows what else)

 

what could it be??? lol

Edited by Azh
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I appreciate all the replies guys, gives me food for thought. :)

 

I am going to try plugging 2 fans directly into the motherboard and leaving the other 4 in the fan controller and seeing what happens.

 

As I said, if these fans had no led I wouldn't have even known there was an issue as they stop spinning, and everything appears to shut down as normal it's just the lights remain on - albeit very dim.

 

Oh and there are no high voltage cables or radio transmitters near me.

 

Edit: Keep it sensible Azh... :)

Edited by AdzUK
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I appreciate all the replies guys, gives me food for thought. :)

 

I am going to try plugging 2 fans directly into the motherboard and leaving the other 4 in the fan controller and seeing what happens.

 

As I said, if these fans had no led I wouldn't have even known there was an issue as they stop spinning, and everything appears to shut down as normal it's just the lights remain on - albeit very dim.

 

Oh and no there are no high voltage cables or radio transmitters near me.

 

Edit: Keep it sensible Azh... :)

 

I am, promise

 

http://i.imgur.com/zWmEz.gif

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  • Corsair Employee

I'm bringing some popcorn, :D maybe you'll bring some sensible suggestions to the table, I wont hold my breath though ;):

 

 

I love how you joined the forums just to troll in this thread.

 

Enjoy your popcorn.

 

You tell me how a PSU is generating DC power without AC power (remember, the PSU is unplugged from the wall) without taking into consideration that the nature of capacitors is to hold a charge.

 

Go ahead. I'll wait.

 

This is what you sound like to me so far: "The PSU is faulty because it's putting out DC power with no AC source." You're telling me that makes sense?

 

Like I said, if the PSU was still plugged in, I'd say it's a faulty switch. But he's pulled the power from the wall.

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UPDATE:

 

I have just shutdown the PC, switched off the PSU from the back.

 

Unplugged 2 fans from fan controller, the light obviously now goes off. I've plugged the fans directly into the motherboard and the fan light comes back on. This completely eliminates the fan controller. The motherboard is obviously getting some power coming from the PSU even thought the PSU is switched off.

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And the PSU is also unplugged, right? Because as long as that PSU is plugged in and you're getting power with the switch off, we can assume faulty switch. But if you unplug it from the wall, that eliminates the switch since there should be no AC power.

 

I just talked to one of the engineers at Corsair about this and he agrees with me.

 

The 1000W has a longer hold up time and more capacitors on the secondary side than the 700W. They're holding a charge longer.

 

The other possibility is this: Do you have anything plugged into the PC that holds any kind of charge? For example: are you using a USB port to charge anything? While the USB uses +5V and the fans are using +12V, there could be some sort of defect that is allowing the +5VSB to bleed over to the +12V. It's highly unlikely, but you can't rule anything out.

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Haha ^

 

And the PSU is also unplugged, right? Because as long as that PSU is plugged in and you're getting power with the switch off, we can assume faulty switch. But if you unplug it from the wall, that eliminates the switch since there should be no AC power.

 

I just talked to one of the engineers at Corsair about this and he agrees with me.

 

The 1000W has a longer hold up time and more capacitors on the secondary side than the 700W. They're holding a charge longer.

 

Switch isn't faulty as it makes no difference whether PSU is unplugged or whether just the switch is off.

 

I would leave the PC off for longer to see how long the fans actually stay lit but I need to use it almost everyday due to work as well as the odd gaming session here and there. I am off on holiday next month and the PC will be off for a week. If I come back and the fans are still on, that's some power those capacitors are holding.. :D:

 

The other possibility is this: Do you have anything plugged into the PC that holds any kind of charge? For example: are you using a USB port to charge anything? While the USB uses +5V and the fans are using +12V, there could be some sort of defect that is allowing the +5VSB to bleed over to the +12V. It's highly unlikely, but you can't rule anything out.

 

Nothing plugged in but that was something that was already suggested to me.

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... dribble.

 

you've said:

 

the OCZ 700w psu has smaller capacitors / (do you mean capacitance?) hence why it keeps the fan controller / leds lit for a short while (you're wrong of course as the FAN LEDs switch off straight away)

 

the Corsair 1000w psu has 'more' capacitance hence why it allows to keep the fan controller AND THE FAN LEDs lit ... was it 18hrs and counting?

 

nobody is disputing what a capacitor does, it appears this 'special' PSU is releasing charge into the PC after the PC is switched off, if this is the case - is this a feature (lol) or fault? ...I know my ax1200i doesn't do this

 

 

I love how you joined the forums just to troll in this thread.

 

This is what you sound like to me so far: "The PSU is faulty because it's putting out DC power with no AC source." You're telling me that makes sense

 

lol what are you on about, please quote where I have spurted that crap? you obviously want to believe that ...maybe the 'real' corsair engineer should come on this thread and give a sensible suggestion as there is certainly some 'thin air. ;):' coming out of you :roll:

 

anyways so adz:

 

you've tried the following with the same issue:

 

a new molex cable

a new connector on the psu

plugging the fans to the motherboard directly

 

hope you get it sorted soon, don't want the rest of your hardware to go 'lights out' (no pun intended).

 

 

Good luck

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  • Corsair Employee
Haha ^

 

Switch isn't faulty as it makes no difference whether PSU is unplugged or whether just the switch is off.

 

I would leave the PC off for longer to see how long the fans actually stay lit but I need to use it almost everyday due to work as well as the odd gaming session here and there. I am off on holiday next month and the PC will be off for a week. If I come back and the fans are still on, that's some power those capacitors are holding.. :D:

 

Nothing plugged in but that was something that was already suggested to me.

 

What is the make/model of the fans? I'd like to look into them.

 

Also, do you have a DMM to measure the voltage on the +12V? As the caps drain, that voltage should drop, but it could still drop to a low enough voltage that can keep the LEDs lit up. A +12V LED doesn't necessarily need +12V to stay lit.

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  • Corsair Employee

See if you can get your hands on a DMM. You should be measuring at least 1V and that could be enough to keep those LEDs lit up.

 

I'm going to see if I can duplicate the issue here. If this is normal, I should be able to replicate the issue and I should be able to get a voltage reading after power off. I'll see how low that voltage is and how long it holds that charge.

Edited by jonnyguru
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