Question AIO with RGB on Motherboard With No 3-Pin/RGB Header

Oct 23, 2020
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Hello

I'm gathering my parts for my first ever build. My CPU (Ryzen 5 3600) has a Wraith Stealth cooler, but I know this is pretty noisy and not great if I plan to OC at all. Plus my case apparently has pretty bad air flow.

Anyway, I like the idea and style of an AIO. The Cooler Master ML240L is a decent price..... My problem comes from my motherboard (MSI B450M-A Pro Max) not having a 3-Pin connector or RGB header. So would I be able to get the leds working? The board doesn't have a Pump Fan header. I can only see 1x CPU fan connector and 1x 4-Pin system fan connector.

I feel like I'll have to either return my board for something else, or go with an air cpu cooler with push-pull fans either side.
 
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Paperdoc

Glorious
Ambassador
Yes, this can work. As you may notice, the fans for the radiator each have two cables from them. One is for the fan motor and these end in common 4-pin fan connectors; the other is for the lights in the frame, and ends in a wider connector with 4 holes. We'll deal with them separately.

First, the fans and pump of this AIO system. You have only one CPU_FAN header for them, so we'll use a little design quirk of 3-pin fans. The PUMP unit's fan connector will have only three wires from it, and likely a 3-pin fan connector. If you plug such a "fan" into a mobo a header that is using the new PWM Mode to control fan speed (and that is how your CPU_FAN header works), that fan will always run full speed with no control. As it happens, that is exactly what a PUMP should do - always run full speed. So, you need to get a common SPLITTER that converts your single CPU_FAN header into two outputs. Look at it closely and you'll see that one of those outputs has all 4 pins, and the other is missing Pin #3. This is how the Splitter ensures that the speed of only ONE fan (the one plugged into the output with all its pins) is fed back to the mobo. (More than one speed signal causes big confusion and errors at a fan header.) It may seem odd, but ensure that the cable from the PUMP unit (3-pin design) is the one that is plugged into the Splutter output with ALL FOUR pins. Then look in your AIO kit for the other fan Splitter supplied with it. Plug that into the other output of your first Splitter, and connect both rad fans to that.

The CPU_FAN header's main focus is on controlling the speed of its cooling fans to keep the temperature of the CPU chip (as measured by a sensor inside the chip) correct. It also has an important second function: monitoring the speed of its fan for possible FAILURE, and it does this by checking that it HAS a good speed signal. If it does not get that, it will certainly put on your screen a prominent warning of fan failure, and MAY (depends on the mobo design) shut down your entire system quickly without even waiting for the CPU temp sensor to detect overheating. In your case, you will connect three items to that header - the pump and two rad fans - but the header can only deal with the speed signal from one of those three. Of them the most important to monitor for failure is the PUMP - CPU cooling is pretty much nil if the pump is not running, So, by ensuring that the PUMP is the one item plugged into the output arm of the fist Splitter that HAS all four pins, you ensure that the PUMP speed signal is what the CPU_FAN header will monitor for failure. You will never "see" the speed of the two rad fans, but that is not vital, and the mobo does not use that info. But from time to time YOU should just look and verify that the rad fans are working.

Now for the lights. You do not have any mobo header for lights. But the AIO system comes with a manual control box and cabling to power them from a PSU power output. With that box's three buttons you can set and change how the RGB lights in the fans and pump work. The kit includes an RGB three-output Splitter to connect all three of those devices' lighting cables to that manual control box. One thing to watch for. The connectors for the RGB lights have 4 holes in them. On each connector, ONE hole at one end will be marked, and that is the 12 VDC power line. When connecting these lighting cables, always match up the marked pins and holes.
 
Oct 23, 2020
12
1
15
0
Yes, this can work. As you may notice, the fans for the radiator each have two cables from them. One is for the fan motor and these end in common 4-pin fan connectors; the other is for the lights in the frame, and ends in a wider connector with 4 holes. We'll deal with them separately.

First, the fans and pump of this AIO system. You have only one CPU_FAN header for them, so we'll use a little design quirk of 3-pin fans. The PUMP unit's fan connector will have only three wires from it, and likely a 3-pin fan connector. If you plug such a "fan" into a mobo a header that is using the new PWM Mode to control fan speed (and that is how your CPU_FAN header works), that fan will always run full speed with no control. As it happens, that is exactly what a PUMP should do - always run full speed. So, you need to get a common SPLITTER that converts your single CPU_FAN header into two outputs. Look at it closely and you'll see that one of those outputs has all 4 pins, and the other is missing Pin #3. This is how the Splitter ensures that the speed of only ONE fan (the one plugged into the output with all its pins) is fed back to the mobo. (More than one speed signal causes big confusion and errors at a fan header.) It may seem odd, but ensure that the cable from the PUMP unit (3-pin design) is the one that is plugged into the Splutter output with ALL FOUR pins. Then look in your AIO kit for the other fan Splitter supplied with it. Plug that into the other output of your first Splitter, and connect both rad fans to that.

The CPU_FAN header's main focus is on controlling the speed of its cooling fans to keep the temperature of the CPU chip (as measured by a sensor inside the chip) correct. It also has an important second function: monitoring the speed of its fan for possible FAILURE, and it does this by checking that it HAS a good speed signal. If it does not get that, it will certainly put on your screen a prominent warning of fan failure, and MAY (depends on the mobo design) shut down your entire system quickly without even waiting for the CPU temp sensor to detect overheating. In your case, you will connect three items to that header - the pump and two rad fans - but the header can only deal with the speed signal from one of those three. Of them the most important to monitor for failure is the PUMP - CPU cooling is pretty much nil if the pump is not running, So, by ensuring that the PUMP is the one item plugged into the output arm of the fist Splitter that HAS all four pins, you ensure that the PUMP speed signal is what the CPU_FAN header will monitor for failure. You will never "see" the speed of the two rad fans, but that is not vital, and the mobo does not use that info. But from time to time YOU should just look and verify that the rad fans are working.

Now for the lights. You do not have any mobo header for lights. But the AIO system comes with a manual control box and cabling to power them from a PSU power output. With that box's three buttons you can set and change how the RGB lights in the fans and pump work. The kit includes an RGB three-output Splitter to connect all three of those devices' lighting cables to that manual control box. One thing to watch for. The connectors for the RGB lights have 4 holes in them. On each connector, ONE hole at one end will be marked, and that is the 12 VDC power line. When connecting these lighting cables, always match up the marked pins and holes.
Wow, thank you. That's a lot of info. So, the AIO should have accessories inside to connect it all to the included controller?

And all I should need to buy is the splitter for the CPU_FAN connector? Any recommendations on what and where to get one?
 

Paperdoc

Glorious
Ambassador
Yes, the AIO kit you linked to has several things for connection, including even a cable you will NOT need for connecting to a mobo header (you don't have one).

Two-output 4-pin Splitters are VERY common and cheap, so you can get one at any place that sells computer accessories. They are so cheap (often $2 to $5) that buying on-line (and paying shipping costs) does not work unless you also are ordering other stuff.
 
Oct 23, 2020
12
1
15
0
Yes, the AIO kit you linked to has several things for connection, including even a cable you will NOT need for connecting to a mobo header (you don't have one).

Two-output 4-pin Splitters are VERY common and cheap, so you can get one at any place that sells computer accessories. They are so cheap (often $2 to $5) that buying on-line (and paying shipping costs) does not work unless you also are ordering other stuff.
I see. Well I've got to order the AIO online so hopefully they have splitters as well that I can add to my basket.

How would it all work if I wanted to add 2 or 3 rgb exhaust fans? I presume I'd end up at the point where just returning and exchanging my mobo would be the best idea for the sake of simplicity.

Am I just as well getting a decent tower cooler with fans on either side doing pull-push? I presume if they were RGB fans then I'd still be needing the splitter? I can get my head around moat things but motherboards just confuse me.
 

Paperdoc

Glorious
Ambassador
OK, let's expand a bit more on lights first. There are two major types of RGB lighting systems dominating the market now, with a few that differ mainly on what kind of connector they use. The two types are INcompatible, so you cannot mix them on the same mobo header.

Plain RGB uses a 4-pin connector with a common 12 VDC power supply line and one separate Ground line for each of the three colours of LED's along the strip. All Red ones are on the same Ground line, all Green another, all Blue on the third. The controller manipulates each of the three Ground lines to make thousands of colours that it changes, but at any one moment the entire light string is one colour. The connectors all have a mark on one end identifying the +12 VDC contact, and you MUST match them up at every connection point.

Addressable RGB (aka ADDR RGB, ARGB, or Digital RGB) uses a 3-pin connector that looks a lot like the 4-pin one with one pin missing. It supplies common +5 VDC and Ground lines, and a digital Control Line. Along the strip, the three LED colours are organized into Nodes. Each Node contains one LED of each of the three colours plus the node's own control chip. That chip has its own individual address and it listens to the Control Line and does what it is told to do with its three LED's. So at any one moment, every Node in the string can be a different colour, and the displays can be more complex. Photos of these systems often show rainbow displays that the plain RGB system cannot do. Because both the voltage supplied and the method of display control are so different, these cannot be mixed with plain RGB on the same circuit.

To get these lights working you need a controller of the same type as the lights you buy. The controller is both the power source and the display control device. The simplest are what you saw with that AIO system - a box connected by cables to a PSU power source and to the light strings, with typically three manual buttons to set some of the display parameters. There is no software involved in this, and all control is by the buttons on a box connected by cable. Many third-part RGB systems (either strips or fans with lights or both) come with a variation on this: the control box you handle is battery-powered and uses radio signals to the actual controller inside your computer case, but it is still an all-manual control system. Then there are LOTS of mobos that have lighting headers built into them. Some come with none (as does the one you mentioned), some have one or two plain RGB headers, some have only one or two ADDR RGB headers, and some have both types. Mobo makers all have their own utilities they supply with the mobo with their brand names (e.g. MSI Mystic Light, ASUS Aura Sync, Gigabyte RGB Fusion, etc.) and these can power and control BOTH types of headers on their maker's mobos. So the NAME of the lighting utility does NOT tell you the TYPE of header on the mobo! When you go to match the lighting type you buy (4-pin 12 VDC plain, or 3-pin 5 VDC ADDR) to the mobo HEADER, you need to see the mobo's specs to be sure which header(s) it has. Control of the lights in these cases is entirely by the software tool to manipulate the mobo headers' signals. Then the fourth option is third-party lighting control boxes often sold with lights or lighted fans by their makers that use a different connection system from the manual boxes. These boxes connect to the PSU for power and to the lights, but also use up one USB2 header on the mobo. You are supplied with a software utility by the maker and must load and run that. It uses the USB2 link to communicate instructions to the controller box. These utilities also may integrate controls for fans and other devices made by the same supplier. Some of them use non-standard connectors for the lights they supply, so watch for that. And another feature of the third-party units (whether manually- or software-controlled) is they MAY have an option to accept input of signals from a mobo header and relay them on to their lights instead of using their own display controls.

Normally IF you get a mobo with either type of lighting header on board, you get one or maybe two such headers. So any more fans (or strips) than that, you must also get an RGB Splitter or ARGB Splitter to make more connections. The mobo manuals normally will tell you the max current each header can supply to the lights connected to the header. Then you need the specs for the light strip or fan about what is the max current consumed by the LIGHTS ONLY in the device. Many tell you this if you look closely, but some do not. So you are left to bet, but most light strips (or single fans) consume not more than 0.35 A for the lights only (excluding the fan motor which does NOT draw any current from the lighting header of the mobo.)

With that background, back to your most recent post. I said earlier you CAN make your original scheme work. You have as supplied three lighting devices and a manual controller box with a 3-output RGB Splitter. Then you are considering adding three case fans that also have PLAIN RGB lights in them (remember the ones you have are the plain RGB type) and wonder how to power and control these additional ones. I would guess (no specs available, I'm afraid) that the manual control box you have with the AIO system could supply them, too. To do that you would need an additional plain RGB Splitter with at least four outputs - three for the new fans, and a fourth to plug in the 3-output Splitter you already have with the AIO system. Here is an example of a two-pack of those

https://www.amazon.com/Splitter-Connector-Strips-12inch-4Splitter/dp/B072K21JVF/ref=sr_1_7?dchild=1&keywords=RGB+Splitter&qid=1604195117&sr=8-7

It has female connectors on all arms, and comes with four gender-changer adapters to convert its outputs to males.

Alternatively, you could buy a different mobo that has plain RGB headers on it, but you still will need at least one RGB Splitter to connect three case fans to one header plus the AIO lights to another header (using Splitter supplied), OR a 4-output Splitter if the mobo has only one plain RGB header. Your AIO system has wiring included that would allow you to feed the mobo header's signals to the lights so you do not have to use the manual buttons to change them.

In buying case fans, keep in mind that the only mobo SYS_FAN header on the board you mentioned first is a 4-pin type ONLY and you MUST buy 4-pin PWM fans to use with that. It cannot control the speed of 3-pin fans. If you are buying a different mobo, its case fan headers MAY have options to control either fan type.
 
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