Wierd ARGB/Fan Hub issue

imaddicted2u · 08 Aug 2023

Got 2 of these ARGB/Fan Hubs and have encountered a strange problem:

Wierd ARGB/Fan Hub issue-argb-fan-hub.jpg

I don't use the ARGB cable, just use the remote. That part works fine.
Both fan hubs work fine in two PCs but neither of them will control fan speed in one other PC. The fans always run at full speed in it, as though the PWM is not connected. In the PCs that the hubs work in, disconnecting the motherboard fan plug make the fans run full speed. The ASUS M5A97 R2.0 motherboard has 4 X 4pin fan ports and the fan hub doesn't control fan speed in any of them, RPM is displayed in SpeedFan app though, it reads the speed of the fan that's plugged in to the red fan jack.
Every one of those 4 ports controls fan speed and displays RPM when I plug fans directly in to them.
The 4 pin fan plug from the hub only has 2 wires connected, PWM and RPM, there is no power or ground connection.
Should be a plug it in and it works deal, it is on two PCs but not the third. Anyone ever seen an oddball problem like this?

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Thanks admin, for moving this, wasn't sure where it belonged.

RoadBlaster · 08 Aug 2023

The red plug will go to the cpu fan & the rest are connected with only pwm from the 2-pin input, as you can not connect all 4 speed senses, only 1. Power will be provided by the sata plug on the fan splitter PCB.

In the bios there may be a fan setting were it says PWM or Voltage controlled, which needs to be PWM.

Does the fan on the cpu change speed when connected directly to the cpu 4-pin skt or stay at full speed?

Can you also provide a close up of the underside of the fan splitter pcb?

imaddicted2u · 08 Aug 2023

RoadBlaster said:

The red plug will go to the cpu fan & the rest are connected with only pwm from the 2-pin input, as you can not connect all 4 speed senses, only 1. Power will be provided by the sata plug on the fan splitter PCB.

In the bios there may be a fan setting were it says PWM or Voltage controlled, which needs to be PWM.

Does the fan on the cpu change speed when connected directly to the cpu 4-pin skt or stay at full speed?

Can you also provide a close up of the underside of the fan splitter pcb?

I'd have to take it apart to show you the bottom. The board is sandwiched between 2 plastic pieces. The bottom one is black.
Any 4 pin PWM fan can be connected to the red plug, not just CPU. The red plug passes the rpm back to the motherboard and reads the PWM from the motherboard. It then passes the PWM signal to the rest of the fans. There is no way for the hub to know whether it's connected to the CPU fan or any other fan. I prefer to let the motherboard control the CPU fan and let the hub control the case fans. I'm running it that way in 2 other PC's.
As I posted above, the odd thing is the speed is not controlled when either of the 2 fan hubs are connected to this ASUS M5A97 R2.0 motherboard , yet the speed is controlled when the fans are connected directly all of the case fan ports. So, the BIOS settings are correct but I re-checked them again.
If I do put the CPU fan on the red jack, the CPU fan and all fans connected to the hub runs full speed.
PWM fans, by default, run full speed if they don't receive the PWM control signal. So, the hub, for some reason isn't seeing that signal, yet fans connected directly do see the PWM signal. Same hubs and connecting wires work in other computers.
It just doesn't make sense, there is no rocket science involved.

RoadBlaster · 09 Aug 2023

imaddicted2u said:

I'd have to take it apart to show you the bottom. The board is sandwiched between 2 plastic pieces. The bottom one is black.
Any 4 pin PWM fan can be connected to the red plug, not just CPU. The red plug passes the rpm back to the motherboard and reads the PWM from the motherboard. It then passes the PWM signal to the rest of the fans. There is no way for the hub to know whether it's connected to the CPU fan or any other fan. I prefer to let the motherboard control the CPU fan and let the hub control the case fans. I'm running it that way in 2 other PC's.
As I posted above, the odd thing is the speed is not controlled when either of the 2 fan hubs are connected to this ASUS M5A97 R2.0 motherboard , yet the speed is controlled when the fans are connected directly all of the case fan ports. So, the BIOS settings are correct but I re-checked them again.
If I do put the CPU fan on the red jack, the CPU fan and all fans connected to the hub runs full speed.
PWM fans, by default, run full speed if they don't receive the PWM control signal. So, the hub, for some reason isn't seeing that signal, yet fans connected directly do see the PWM signal. Same hubs and connecting wires work in other computers.
It just doesn't make sense, there is no rocket science involved.

You connect the red output to the CPU fan because that fan may be smaller than your case fans which may be bigger & spin at a different rate, so when you temp goes up the the correct fan speed is monitored for precise cooling.

A fan splitter is design to spin all 4 ouputs at the same PWM rate, it seems you may be one of a few that is doing it wrong.

You also did not mention if you plug the power into the fan splitter, you just rather repeated your 1st question without answering the questions I asked?

I know exactley how a fan splitter works, as I can design & build my own fan splitters, including using power directly from the PSU.

imaddicted2u · 09 Aug 2023

RoadBlaster said:

You connect the red output to the CPU fan because that fan may be smaller than your case fans which may be bigger & spin at a different rate, so when you temp goes up the the correct fan speed is monitored for precise cooling.

A fan splitter is design to spin all 4 ouputs at the same PWM rate, it seems you may be one of a few that is doing it wrong.

You also did not mention if you plug the power into the fan splitter, you just rather repeated your 1st question without answering the questions I asked?

I know exactley how a fan splitter works, as I can design & build my own fan splitters, including using power directly from the PSU.

I must be doing it right in 2 PCs and wrong in one, when they are all wired up the same. That hub can't tell the difference between a case fan or a CPU fan.
All my fans are 120MM, including CPU fan, This splitter can power 8 fans. I'm connecting the SATA power plug to the hub or it would not spin up any fans at all.
This motherboard has 4 PWM outputs, 3 for case fans controlled by motherboard temperature and 1 for CPU controlled based on CPU core temp.
As I said before, I did try it the way you say, red plug to CPU fan, 2 wire plug from hub to CPU fan jack. Same issue occurs, all fans connected to the hub, including CPU fans run 100% RPM. When I connect the CPU fan back to the original motherboard fan jack it is speed controlled based on core temp properly.
I take the same hub to 2 different PCs with different motherboards and whether I connect the red plug to the CPU fan or a case fan, it works perfectly.
It's as though the PWM signal has no path to ground when connected to the ASUS M5A97 R2.0 motherboard so the fan hub doesn't see it and defaults to 100% fan speeds.
My point was the red plug doesn't HAVE to be connected to CPU fan, it can be connected to any 4 wire PWM fan.
I thought I answered all your questions, except if the power is plugged in, I thought that was obvious.
Sorry if I upset you, I wasn't questioning your knowledge, I have no way of knowing what you know. I've been an Electronic Engineer since 1975, if the answer was simple or obvious, I would not be here posting here.
This seems to be one of life's mysteries.

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I meant to post a pic of my CPU cooler

Wierd ARGB/Fan Hub issue-screenshot-2023-08-09-081344.png

RoadBlaster · 09 Aug 2023

RoadBlaster said:

The red plug will go to the cpu fan & the rest are connected with only pwm from the 2-pin input, as you can not connect all 4 speed senses, only 1. Power will be provided by the sata plug on the fan splitter PCB.

In the bios there may be a fan setting were it says PWM or Voltage controlled, which needs to be PWM.

Does the fan on the CPU fan change speed when connected directly to the cpu 4-pin skt or stay at full speed?

Can you also provide a close up of the underside of the fan splitter pcb?

imaddicted2u said:

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Yes, I see what you are saying but that motherboard is old, look in the bios as it may be set to voltage controlled because with older boards all connections apart from CPU were full blast fans speed, it may need adjusting in Bios?

Modern motherboards have a good fan setting speed to be controlled by CPU, PCH or another temp point inthe mobo bios settings & they are set by default to be working automatically! - older boards may need a change saving?

You have not anoyed me, I was just stating facts.

imaddicted2u · 09 Aug 2023

You make a good point about the MB being old. It was early in the development of PWM fan control . I think it used a floating ground for the PWM signal and they must have adopted a different strategy in later MBs. That would explain why fans work when connected to the fan ports but not when the fan hub is hooked up since the 2 wire plug only passes PWM and RPM, not ground and the hub expects to get PWM ground from the SATA power plug and can't since it's floating.
This MB has AMD Cool n' Quiet, controls the fans on the CPU core temp sensor and 3 different temp sensors on the MB. There are no settings in BIOS other than to turn Cool n' Quiet off and to set low rpm alarm limits for the fans. ASUS had an app to set custom temp curves but they pulled support and it not longer works. The fan plugs only output PWM.
Anyway, I settled on having the CPU fan controlled by the CPU fan plug, 2 case exhaust fans on FAN1 and Fan2 and 3 case intake fans on the fan hub. I'm stuck with those running 100%
Thanks for your input, I appreciated it.
It's my wife's PC, she likes her pretty lights.
The way I oriented the fans acts like a push pull on the cpu cooler and the GPU gets lots of air from below.

Wierd ARGB/Fan Hub issue-uphere-cpu-cooler-fan-directions.jpg

EDIT: Forgot to mention, the fan is mounted on top of the case because a MB power connector hits the fan so I couldn't put it inside the case.

RoadBlaster · 09 Aug 2023

imaddicted2u said:

You make a good point about the MB being old. It was early in the development of PWM fan control . I think it used a floating ground for the PWM signal and they must have adopted a different strategy in later MBs. That would explain why fans work when connected to the fan ports but not when the fan hub is hooked up since the 2 wire plug only passes PWM and RPM, not ground and the hub expects to get PWM ground from the SATA power plug and can't since it's floating.
This MB has AMD Cool n' Quiet, controls the fans on the CPU core temp sensor and 3 different temp sensors on the MB. There are no settings in BIOS other than to turn Cool n' Quiet off and to set low rpm alarm limits for the fans. ASUS had an app to set custom temp curves but they pulled support and it not longer works. The fan plugs only output PWM.
Anyway, I settled on having the CPU fan controlled by the CPU fan plug, 2 case exhaust fans on FAN1 and Fan2 and 3 case intake fans on the fan hub. I'm stuck with those running 100%
Thanks for your input, I appreciated it.
It's my wife's PC, she likes her pretty lights.
The way I oriented the fans acts like a push pull on the cpu cooler and the GPU gets lots of air from below.

I have a 230mm fan on the side of my case from my old "Server Case", I made a speed control for fans that can not be pwm (3-Pin fans) & have 3 settings about 9.5vdc 10.5vdc then 12v max for summer & winter conditions.

You can buy fan controller front bay (5.25") or "Floppy Disk size" devices for basic switching or speed control with temp sensors.

You cooling looks good with alot flow.

Aslo, PWM is a digital signal, so does not need 0v like optical or co-ax cables do not need it, that would make it a 5-pin connection.

Malneb · 09 Aug 2023

That era of motherboard it will be DC headers, PWM was less common only high end and server grade stuff. You will need to use speed fan to control the fan speed because it will target the fan controller directly.
Most Asus from that time, mid tier Asus at that will be DC and all boards that have this styling that i have come across are DC style.

the docs say 1A (12 W) fan max on the headers so this also lines up to DC headers because this is a common DC fan type.

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I am not overly familiar with this specific MB but all those brown/blue color combos at the time where all the same.

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4 pin does not always mean PWM also.

imaddicted2u · 09 Aug 2023

Malneb said:

That era of motherboard it will be DC headers, PWM was less common only high end and server grade stuff. You will need to use speed fan to control the fan speed because it will target the fan controller directly.
Most Asus from that time, mid tier Asus at that will be DC and all boards that have this styling that i have come across are DC style.

the docs say 1A (12 W) fan max on the headers so this also lines up to DC headers because this is a common DC fan type.

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I am not overly familiar with this specific MB but all those brown/blue color combos at the time where all the same.

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4 pin does not always mean PWM also.

You are guessing.
They are PWM fans.
From the manual:
The CPU fan supports a CPU fanof maximum 1A (12 W fan power)