05-03-2018 01:46 PM
I have a Z230 tower workstation. This workstation has an optional 4pin front fan header in the motherboard. I installed a 4pin fan in that header but it spins at full speed. I didn't find any info regarding this header , if it has pwm control or not. The fan however has pwm control , i tried even removing the chassis fan that has pwm because it adjust it speed according to the chassis temperature and it still spins at full speed. I did not found any options in the bios.
So any info regarding this header is appreciated
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05-03-2018 05:22 PM
what is the header number the fan lead is connected to? and what is the model number of the fan you installed?
there are many, many diffrent fan specs such as voltage/rpm/3 or 4 pin power connections/tempture compensated,
and so on
you can get the fan locations/motherboard connectors from the service manual for your model workstation
05-04-2018 06:04 AM
I have seen the docs that you added the links to, the first one is for z240. In the other ones i have found no info for the front fan header in terms of pwm control.
The fan is 4pin and as i said i tried even the chasis fan that is manufactured by hp and it still spins at full speed , even the fan that i want to add if i plug it in the chassis fan header works ok. So the problem must be in the front fan header. Maybe it does not have pwm control even if there are 4 pins
Later i will see the header number if that helps.
03-02-2019 11:30 PM - edited 03-03-2019 09:33 AM
Most of the HP workstation chassis fans are 92 x 92 x 25 mm fans and the 4-pin headers on the motherboard have standard PWM pinout.... but not all 4 pin headers on all HP workstations vary their speeds. One workaround is to get a nice high quality 3-wire low speed fan such as from Noctua and attach it to the first 3 pins of the 4-pin header. Many of the Noctua 3-wire fan kits ship with a voltage reducing 3.5" long 3-wire fan speed reducer, or two. You can use one of those to reduce the speed to a level you like. There are Low Noise Adapters and Ultra Low Noise Adapters, with different resistor values. I like the ULNA for much of my work on these workstations where I need such fine tuning.... check Amazon or eBay for ULNA if you want to buy them individually. The kit for the Noctua I looked up for this has both a LNA and a ULNA included. I have even piggy backed these in a few cases to increase the net resistor value applied.
The PWM fans HP uses are usually quite high speed ones (best bearings), and then HP applies its PWM braking from the motherboard to them. Thus, if the PWM braking is not working the fan will run at full speed just as if that 4th (PWM control signals from motherboard to rotor) wire was cut. Hence, way too fast. Also, If you take a nice slow 4-wire PWM Noctua fan and put it on a normally functioning HP PWM header it runs way too slow......
So, in your case it is better to just buy a 3-wire Noctua as your workaround and be done with it. Assuming you need a 92mm fan I'd recommend the NF-A9 FLX with its ULNA attached..... that will run at about 1050 RPM. To fit the 3-wire plug on the 4-wire header shave the plastic ridge off the pin 3 side of the 3-wire plug, and leave the pin 1 side plastic ridge alone. Or, hope for a BIOS fix? Or, buy a new motherboard? Bad idea for this elective project. I do add a front fan to virtually all my HP workstation builds, and find if I can have it running roughly at 1k RPM it is nearly silent and does the job I want. A more advanced fan plug method is to harvest a HP 4-pin brown chassis fan plug and carefully transfer the Noctua's 3 wires over to that in the proper order, and I even have added a wire-removed metal insert from another junker fan into hole 4 of the plug end for a better grip on the motherboard header... not really necessary.
You can do a "ghetto mod" to get the fan in, but if there is an official black plastic optional fan holder that is the best way to go. Check what the correct fan size is to ensure it is 92 x 25, or pick another 3-wire Noctua fan if it is not. There is a nice archived post on a "ghetto mod" I've used to pull this off, HERE. As you'll read at the bottom of this old post you really need to understand what pins on the motherboard header are pins 1,2,3 and put your modified 3-wire fan plug on those and not on pins 2,3,4.
EDIT: Looking on eBay.... the internal space for that short tower workstation is limited, and yet there was an option kit E1U64AA 731730-001 that existed to add a front fan/black plastic card guide. I'd bet it was a kit that included a 80 x 80 x 25 mm fan and that it will be virtually impossible to find. Hence, ghetto mod...... and if it is 80mm fan I'd go Noctua NF-A8 ULN with its included ULNA getting you 1100 RPM.
04-13-2019 07:28 AM
Thanx SDH for all the information provided. I accepted it as a solution.
I like to add another way(workaround).
Using a PWM signal splitter like this one
Plug it in the case fan header and all the other fans will be controlled by this header