Akasa PWM 5-fan splitter help

pc_monkey · 2 Dec 2011 at 14:41

I have Akasa PWM 5-fan splitter, model number AK-CBFA03-45. I am 100% sure I have all connections correct, but problem is any PWM fan that gets connected always run at full speed. I have tried 5 different makes of PWM fans and they all run at full speed. But when I connect therm directly to the motherboard they all run accordingly. I have also checked the coloured cables and they are all in their correct positions on the connector. SO what is happening???

Orcvader · 2 Dec 2011 at 14:53

Have you conncted splitter to the correct motherboard 4 pin header? It must be 4 pin, not 3 pin as it uses PWM signals to control the fan speeds.

pc_monkey · 2 Dec 2011 at 15:21

Orcvader said:
Have you conncted splitter to the correct motherboard 4 pin header? It must be 4 pin, not 3 pin as it uses PWM signals to control the fan speeds.

Yes I have, there is only x1 4pin that connects to the MB, and there is only x1 connector that has all 4 connections, the rest are all slaves, the other is a molex connector which is connected to the PSU.

Orcvader · 2 Dec 2011 at 15:27

So all the fans are definitely PWM? Have you tried only one fan on the splitter? What fans are you using?

HeX · 2 Dec 2011 at 15:30

Have you turned on the PWM Fan control within BIOS?

pc_monkey · 2 Dec 2011 at 15:54

Orcvader said:
So all the fans are definitely PWM? Have you tried only one fan on the splitter? What fans are you using?

I have tried TR TY-140 x3, Enermax UCTB12P x2, Enermax UCCL12, and the pwm fan that came with the hyper 212+. I have tried all of my fans and the connectors, one at a time.

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HeX said:
Have you turned on the PWM Fan control within BIOS?

It is on as when I remove the splitter and use the fans by themselves, they run accordingly.

Tealc · 2 Dec 2011 at 15:58

The other Akasa PWM splitters have been known to have a bad connection on occasion. If this is the case then it'll most likely be on the motherboard connector or where they split off.

If you have a multimeter use the Diode function to check continuity between the 4th wire on the motherboard connector and the PWM pins on the slave connectors.

pc_monkey · 2 Dec 2011 at 16:02

Tealc said:
The other Akasa PWM splitters have been known to have a bad connection on occasion. If this is the case then it'll most likely be on the motherboard connector or where they split off.

If you have a multimeter use the Diode function to check continuity between the 4th wire on the motherboard connector and the PWM pins on the slave connectors.

Thanks, that was my initial guess - a bad connection...

I don't have and don't know how to use a multi meter

. I have just spoken to the vendor and they will replace it after they test it (PITA).

pc_monkey · 8 Dec 2011 at 20:01

HI all, the replaqcement turned up today. Immediately connected and tested again, but again I have the same issue.

One thing though, out of frustration, I pulled out the pwm connector and guess what, the fans were still running at full speed. Is this supposed to happen? I'm a bit confused now.

setter · 8 Dec 2011 at 21:08

Are all the fans identical speed models, if not perhaps this is the cause? Ive used the 3 pin unbraided version of the splitter, but always with identical models of fan. As the pwm connector was removed, the fans will be receiving the full 12v from the psu therefore running at full speed.

Orcvader · 8 Dec 2011 at 21:14

k_poh said:
One thing though, out of frustration, I pulled out the pwm connector and guess what, the fans were still running at full speed. Is this supposed to happen? I'm a bit confused now.

It's normal since all the fans on the splitter are powered directly from the PSU. So with no PWM link to the motherboard they'll just run at 100%. Sounds like a problem with the 4 pin header on the board, super wild guess but when you connect a fan directly to it, it runs in 3 pin mode, which can still change the fan speeds. So the 4th pin that's usually for PWM is either faulty or just useless. But as I said, it's a very, very wild guess and I could be wrong.

What motherboard do you have?

pc_monkey · 8 Dec 2011 at 23:42

Orcvader said:
It's normal since all the fans on the splitter are powered directly from the PSU. So with no PWM link to the motherboard they'll just run at 100%. Sounds like a problem with the 4 pin header on the board, super wild guess but when you connect a fan directly to it, it runs in 3 pin mode, which can still change the fan speeds. So the 4th pin that's usually for PWM is either faulty or just useless. But as I said, it's a very, very wild guess and I could be wrong.

What motherboard do you have?

It is an Asus P8Z68-V but I don't think it is faulty though because I also use a 2-way pwm splitter which works. Using the 2-way pwm splitter, I am monitoring the fan speeds and with no cpu load, they run at minimum speed but when I load IBT or P95, the fans run faster to compensate. The 2-way pwm splitter I am using does not need extra 12v power from other connector (eg. molex) because it directly connects to the motherboard header.

Any more idea ???

Edit:
I will try the other headers and see what happens.

setter said:
Are all the fans identical speed models, if not perhaps this is the cause? Ive used the 3 pin unbraided version of the splitter, but always with identical models of fan. As the pwm connector was removed, the fans will be receiving the full 12v from the psu therefore running at full speed.

I have 2 identical fans I have tested, but it should work even with un identical fans because the pwm monitors only 1 fan, the rest are slaves.

pc_monkey · 9 Dec 2011 at 00:08

I have just tried the CPU header and the 5-way splitter works.

Just flicked my manual and compared the CPU header against the chassis header.
This is what is written:

CPU header from left to right:
1.CPU fan PWM, 2.CPU fan In, 3.CPU fan PWR, 4.GND

Chassis fan header from left to right:
1.+5V, 2.Cha Fan In, 3.Cha fan PWR, 4.GND

I don't know what this means but it looks like the chassis header is not PWM after all