Lian Li Lancool II Mesh RGB Fan Question

Arjit

Hi, I have recently purchase Lian Li Lancool II Mesh RGB case and I am preparing to assemble my build. Came across one point on which need support. Per Lian Li (https://lian-li.com/product/lancool-ii-mesh-rgb/), there are three ARGB PWM 120mm fans provided with this case. But the fans have 3 pins only. PWM fans contain 4 pins. Right? Is there a difference in the model Micro Center has and Lian Li's current model?

JS_MC

Hello @Arjit Welcome the Community!

Per Lian Li's website, these are not PWM fans they are ARGB 3pin fans that spin at 1300 RPM.

Fan Specs: 3 x included 120mm 3-PIN 1300 RPM ARGB fans Rated Speed:1300RPM ±10 % Air Flow:49.14CFM Noise:25.0dB(A)

Hope this info helps!

Arjit

Hi @LandShark
Per Lian Li (https://lian-li.com/product/lancool-ii-mesh-rgb/) I do see they are calling out that they are providing three ARGB PWM fans with the case. Here's the snapshot of the page. Please see the second paragraph in the description. It calls out "Packing three ARGB PWM 120 mm fans".


Here's a better image of the same page (text only):

JS_MC

My apologies! You are correct!

I've done more research on the topic and have learned a bit more about this. Here's what I've found.

There are both 3 and 4 pin PWM

The two designs work differently and require different modes to control their speeds.
3-pin fans have these connections from mobo header to fan:
Pin #1 - BLACK - Ground
Pin #2 - RED - +DC voltage varying
Pin #3 = YELLOW - Speed pulse signal

The female (with 3 holes) connector on the end of the fan's wires has two ridges on one side just outside the Pin 1 and 3 locations, and these fit over a plastic tongue sticking up from the base of the male (with 3 pins) the header on the mobo, so you can only plug the fan in one way - no errors.
The fan is powered by Pins 1 and 2. The mobo header varies the voltage on Pin #2 from 12 VDC (max speed) down to about 5 VDC. Any lower voltage may cause the fan to stall and usually cannot start up a fan that is not turning. This Mode of control is called Voltage Control Mode or DC Mode, and it is the ONLY method of controlling the speed of 3-pin fans. The speed signal on Pin #3 is a series of pulses (2 per revolution) generated inside the fan motor and sent back to the mobo on this line to be counted. That's how the mobo can tell you the speed of a fan. But the mobo does NOT use that signal to control speed. Automatic control of speed (if you allow that to be done, which is the default setting) is based on the actual TEMPERATURE measured by a sensor, and on control system targets pre-set in BIOS (or, in some cases, adjustable by you). There is always a temperature sensor built into the CPU chip itself, and it is used by the mobo CPU_FAN header to guide the speed of that CPU cooler. There is a separate sensor built into the mobo (sometimes more than one for you to choose) at a location decided by the mobo maker, and this should be used to guide the speeds of case ventilation fans connected to the SYS_FAN or CHA_FAN headers.

The newer 4-pin fan design is different mainly in the method of control. The new design includes some backward compatibility features with the older 3-pin system, but they are not completely interchangeable. The uses of the wires are VERY similar, and the design of connectors is such that you CAN plug any 3- or 4-pin fan into any 3- or 4-pin header, and they will work to some extent (more later). The standard wire colors used for 4-pin systems are NOT the same as those for 3-pin ones above. The signals here are:
Pin #1 - BLACK - Ground (same)
Pin #2 - YELLOW - +12 VDC constant
Pin #3 - GREEN - Speed pulse signal (same)
Pin #4 - BLUE - PWM signal

Hope this info helps but I'd be happy to discuss this further if you have more questions!

Arjit

Hi @LandShark
Thanks for the explanation and yes agree with the 3pin vs 4pin. So what I understand is that the Performance Model which has a fan control switch at the top of the case has PWM 4 pin fans and the RGB version has 3 pin fans?

JS_MC

Yes, it does appear that way!

The performance case with the fan controller also asks that you be sure to use 4-pin PWM fans with their controller. However, it does support both 3 and 4-pin fans.