Question Case Fan LED Not Turning Off

Dec 3, 2018
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I have a really old case, but it works for what I do so I still use it. The 200mm side panel fan stop working so I decided to buy a new one. The one I got is a Cooler Master Megaflow 200mm. I screwed it in and plugged it into the fan controller that all the other case fans are plugged into. The LED switch on the top of the case is suppose to turn off all the LEDs on the case fans, but the Cooler Master fan that I got keeps its LEDs on.

Is there a quick little fix or do I need to buy a new fan?
 
Dec 3, 2018
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Does the new fan's LED stay on when the unit is asleep or turned off? Or does this only apply to trying to manually turn the LEDs off via the switch for the original lighting?
The LED lights do turn off when the PC is turned off, and they turn on when the PC is turned on. But the LED button connected to the hub is not turning off the LEDs on that certain fan.
 
For your case fans, obviously there are separate wires for the fan motors and the LED's in the case, so that a case front panel switch can turn off the LED's as you wish. For that new fan, things are different. It is what's called a LED Fan, meaning that the LED's in its frame are connected in parallel with the fan motor so that they always light up whenever the fan is running. There is no way to separate those LED's from the motor electrically. Your case LED switch has NO effect on that fan's LED's.
 

Darkbreeze

Titan
Moderator
Yep. That was going to be my exact point which is why I asked if they turn off when the whole unit is asleep or off. That Megaflow gets power for it's LED through the normal wiring, it does not have extra wires for the LED like your case fans connected to the hub that came with the case do.
 
Dec 3, 2018
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Yep. That was going to be my exact point which is why I asked if they turn off when the whole unit is asleep or off. That Megaflow gets power for it's LED through the normal wiring, it does not have extra wires for the LED like your case fans connected to the hub that came with the case do.
For your case fans, obviously there are separate wires for the fan motors and the LED's in the case, so that a case front panel switch can turn off the LED's as you wish. For that new fan, things are different. It is what's called a LED Fan, meaning that the LED's in its frame are connected in parallel with the fan motor so that they always light up whenever the fan is running. There is no way to separate those LED's from the motor electrically. Your case LED switch has NO effect on that fan's LED's.
You you guys perhaps point me to an LED fan that would work with the switch?
 

Darkbreeze

Titan
Moderator
Probably, only the ones that came with it. I've never even seen this type of fan before on old systems so it is likely that it is a proprietary type design.

What is the case model? What is the model of the old fan? There should be a decal on the back of the old fan with the model.
 
Dec 3, 2018
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Probably, only the ones that came with it. I've never even seen this type of fan before on old systems so it is likely that it is a proprietary type design.

What is the case model? What is the model of the old fan? There should be a decal on the back of the old fan with the model.
I got this replacement fan a while back actually. And I really didn't mind the LED switch not working for it since I never really used the switch, so I ended up throwing out the other fan. I am on the forums now because I thought it would be cool if I fixed it just in case I need to sell it in the future.
 

AllanGH

Commendable
Mar 10, 2019
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I try to steer clear of LED fans, for the most part, but do have a couple machines with some installed, and have looked-over their construction.

It appears that, in most instances, you can disconnect the LEDs from the fan hub, itself (there are usually wires running radially outward from the hub, to the LEDs, which can be cut), after which the wires can be paralleled and a current limiting resistor added. From there, it's a matter of adding wire of sufficient length to connect it to whatever drives your other LEDs.

However, that fan is equipped with a 'sleeve bearing' which isn't going to last you a long time, relatively speaking.

If the LEDs really bug you, the easiest thing to do might be just to cut the wires to them, so that they aren't on with the computer shut down.
 
Dec 3, 2018
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I try to steer clear of LED fans, for the most part, but do have a couple machines with some installed, and have looked-over their construction.

It appears that, in most instances, you can disconnect the LEDs from the fan hub, itself (there are usually wires running radially outward from the hub, to the LEDs, which can be cut), after which the wires can be paralleled and a current limiting resistor added. From there, it's a matter of adding wire of sufficient length to connect it to whatever drives your other LEDs.

However, that fan is equipped with a 'sleeve bearing' which isn't going to last you a long time, relatively speaking.

If the LEDs really bug you, the easiest thing to do might be just to cut the wires to them, so that they aren't on with the computer shut down.
The fans and their lights turn off when my PC does. Its the LED switch that not turning of the LEDs on the 200mm fan I got by the press of a button.
 

Darkbreeze

Titan
Moderator
How many wires/pins are there on the original fans, or, if the LED lighting has separate wiring, is it a two pin? Can you post an image of the connectors for the original type fans?

Or, what is the case model, that the fans came with?
 

Darkbreeze

Titan
Moderator
Yeah, that didn't tell me anything. I'm talking about disconnecting any wiring coming from one of the original fans to the hub, and taking pictures of those connectors or connector. That way we can see EXACTLY what sort of connector or connectorS we are dealing with. Do you not know the model of the case?

Pictures of the case front, top and side might help to identify it, maybe.
 
In the upper photo if that really is the back of the case switch, we are not seeing the cables from the switch to the fans etc. What it does show, though, is the power input to the switch assembly via a common 4-pin Molex connector. That source provides both 12 VDC and 5 VDC power plus Grounds. 12 VDC can be used to provide full-speed operation of fans, whereas 5 VDC would be needed to power LED's separately. More complex switching could also produce a "medium" speed for the fans.

I note also that there appear to be red LED lights in BOTH the fans and other items like the control buttons. So at the very least there are LED's independent of the fans but probably under control of the light switch. So MAYBE the fans themselves do not actually have any LED's in their frames. MAYBE all the front lights are separate LED units spread around the case.
 

AllanGH

Commendable
Mar 10, 2019
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OK....so the switch set-up looks like a relay switching either 12VDC or 5VDC to the LEDs, with the press of a button to toggle the LED on-off state....so, when you press the "LED" button on the top of the case, that single button press toggles your LEDs off, if they are on, and on, if they are on?

If so, you can do as I mentioned earlier, and just route the LED connection to your switch.
 

Karadjgne

Titan
Herald
I have a CM 690 II Advanced, it's got a blue led switched fan in front.

There's 3wire output from the fan, to a 3pin motherboard connection in the standard layout. There's a second wire goes toa 2pin, goes to the switch in the case. The 12v hot is tapped at the motor point, goes through the switch, back to the leds and finally back to the ground.

So what you end up with is a 3pin DC fan, that responds exactly like any other 3pin DC fan, except it has a seperate 12v hot (same source as the fan motor) with a switch in-line for the leds.

That's how CM has been doing switchable leds like in a couple of the HAF cases.

The CM mega flow is just a DC fan with a molex connector that comes with a molex to 3pin adapter. There's no way to turn off the leds without affecting the fan operation.

The only way around that is to interrupt the 12v feed going to the first led on the fan itself (not the ground side) and after robbing the old fan of its connector and wire, putting the switch leg in series with the hots. Leave the ground leg seperate.

@Paperdoc
I'm not so sure about the 5v feeding the leds. Those are still standard 3pin fans, not proprietary. I'd suspect that there's a 5v/9v/12v switch, for low/med/high speeds at set voltages, so uses 5v-12v potentiometer. From my prospective, that picture is purely a fan control switch, the leds themselves having an off/on switch that's seperate. Nobody uses 5v leds in a 12v fan, and if they did, you'd still have a second lead for the leds, seperate from the 3pin fan power, going to a toggle switch.
 
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Darkbreeze

Titan
Moderator
There's 3wire output from the fan, to a 3pin motherboard connection in the standard layout. There's a second wire goes toa 2pin, goes to the switch in the case. The 12v hot is tapped at the motor point, goes through the switch, back to the leds and finally back to the ground.
Yep, pretty sure that's exactly what I said he'd find, earlier.

Need to KNOW if those fans have two separate leads coming off them and so far, still haven't seen any images of the connectors coming off the fans, on the ends of the cables coming from the fans themselves.

Either way, it's not going to work with that Megaflow. I'd bet those are proprietary fans.

Anybody know what case that is?
 
Karadjgne, let me explain my thinking. Unfortunately we do not have the real identity of the fans, nor any info on their wiring, so we are guessing. OP claims there are LED's in the fans that are turned on and off by a case front switch. I queried whether those LED's really are in the fans' frames like normal LED fans, or actually are only separate LED units mounted in the case independently of the fans. No answer on that, either.

However, assuming OP's statements are correct, there must be some separate wiring for those LED units. That is not common in LED fans, but you have cited a design that DOES do just that. So MAYBE something like that is in OP's system.

In most LED fans the LED's simply are connected in parallel with the motor supply voltage, whatever that is. In a 3-pin Voltage Control type of fan, this means that the voltage to the fan (and LED's) will range from 12 to 5 VDC, and we know that such fans' lighting does get dimmer at slow fan speeds. Now, almost all such LED's really are designed to work with 5 VDC. My guess is that the LED's actually are fed though a small dropping resistor to prevent overvoltage to them. But of course no maker will discuss that level of detail with buyers who do not need to know this and might just get confused. Now in this particular situation, OP has some kind of switch and case wiring that uses both 12VDC and 5 VDC supplies to the front panel switch, and also appears to have separate wiring to the LED's. As I said, I believe the case itself has a few LED's (like switch ring bezels) independent of the fans, and these MAY be fed only 5 VDC. So IF that is done, it also would be possible to wire a separate 5 VDC supply to any LED's in the fan frames IF they are designed to work on that voltage supply without any dropping resistor. But all that really is speculation, because we do not have enough details.

Bottom line certainly is, as several have said, any common design of LED fan added to the system and plugged into a mobo fan header can NOT have its LED components controlled in the same way unless OP is prepared to do a bunch of custom wiring and detective work. Unlikely.
 

Darkbreeze

Titan
Moderator
I think this, or something like it (Most of which were used on MUCH older systems and are no longer available, in fact, most of the links to these types of fans just return errors now) is what the OP is needing. I can't tell for certain, but it looks to me as though this fan has separate wiring for the fan operation and LED lighting.


Also, it looks like the Megaflow DOES have dual wiring, for use with an LED on/off switch. The one on my spare fan shelf has it, but it's a Molex that has to be used with the type of switch that came in the Cosmos II and Stryker cases IIRC.
 

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