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Ender 3D Pro - Heated head fan mod
- A different approach

What, yet another Ender fan mod? Yes, indeed! So what's that special about this mod? Well, it's a mod that involves less effort and is easier to construct. And the costs are similar to other solutions, or perhaps, less.

Most notably, there is no need to modify the standard fan mounting. Nor is there need for rewiring in the Ender's electronics casing.

The only catch: you will need to do some skillful soldering.

Choice of fan

We can be brief about the choice of the fan. The most commonly used in these mods are Noctua fans. Here, a 40x40x10mm 12 volt dc 3-wire fan is used (NF-A4x10 FLX). Some may argue the capacity is less than the original fan that Ender uses. But the capacity is sufficient in normal circumstances.

Removing the old fan

This should prove no rocket science. With the Allan key that came supplied with the Ender, the two screws holding the fan cover, are removed and put aside. Next, the cooling fan should be removed from the fan cover. Keep the 4 screws and the cooling duct in a save place.

Now the four screws, holding the head fan on the inside of the fan cover, can be removed. Put the screws also aside. Now the fan can be removed from the cover. It may requirer some effort or the use of small pliers to get the fan out.

Cut old fan wires

Once the fan is freed form the cover, the wires running to it must be cut. We need the wires again next and the longer the better, so cut as close to the old fan as possible. If you plan to make use of the old fan for some other project, then cut the wires were they enter the fan cover. This will leave sufficient length to connect the new fan.

The supply adapter

As you may or may not know, the old Ender fan is powered by 24 volt dc. And the Noctua fan comes at 12 volt dc. So we have a mismatch here. There are numerous instructions out on the web that suggest buying a cheap Chinese style buck converter. That is possible, but it has two drawbacks.

It is a relative big module, usually some 2 by 4 by 1 cm. So we have to find a suitable place to mount it, usually the electronics casing of the Ender. And we need only a couple of tens of milli-amps, were as the buck converter can deliver 2 or more amps 💪. So all in all it's a bit overkill.

There is however a more elegant solution. Electronic engineers are quiet familiar with the 3-pin 78xx style linear voltage regulators. It is possible to use one of these, the 7812, which delivers 12 volt at 1 amps max. The drawback is that it converts the difference between 12 and 24 volt into heat. Not much in this case, but still its is not very efficient.

Best of both worlds

Some manufacturers have realized this as well and come with a solution, where they put a miniature buck converter in almost the same size as a 78xx style housing. This will allow for a far more compact design of this mod. And as we will see, it can be done without any modification inside the electronics casing of the Ender.

As said, some manufactures now make this kind of voltage regulator. And any good electronics parts reseller will have a brand of this regulator in their program. Just pick one that is the easiest for you to obtain. The type used here is the R-7812-0.5 from Recom. It can deliver 0.5 amps, which is more than enough for our needs of 50 milli-amps.

Installing the fan

Before we can install the new fan, we need to trim its wires. We also don't need the connector. Cut the length of all the three wires to 50 mm. Then insulate the yellow wire from the tacho with a piece of heat shrink. We will not use this wire. Next, using the original screws, mount the fan with the wires facing towards the bottom of the fan cover. It is the side that points to the printer's bed when mounted.

Back left side view

In the picture on the right the rear of the fan cover is shown. Observe the yellow wire, which is folded neatly between the fan and the bottom rim of the fan cover.

Fan power connection

The fan's power connection is a piece of a paired black and red wire. You can use any type you have available. Here we use a piece of a spare servo motor 3-wire extension cable, from which the third white wire was trimmed of.

✋ Do not use the left over wires that were cut of the Notua fan. These are too short. You could use however one of the longer cables, that comes shipped with the Noctua fan.

The connection wire of the fan, is guided between the top of the fan and the top rim of the fan cover. It leaves the fan cover in the same spot as the old power connection wires.

✋ Don't feed in this connecting wire pair yet, that will have to wait after we are done installing the regulator. For this operation we go to the next picture.

Mounting the regulator

The next step will be mounting the regulator. As can be seen in the picture, it is mounted flush at the bottom right of the fan. Use some super glue to fix the regulator in position.

Back right side view

Now its time to connect our wiring. This is fairly straight forward, so we won't bother with a schematic.

The regulator has three pins. Placing the regulator in front of you and with the text visible and readable, the pins are numbered 1 thru 3, from left to right.

Pin 1 is the input, were the positive of the 24 volt dc of the Ender’s fan supply connects.

Pin 2 is the middle terminal were both the negative of the Ender and the fan connect.

Pin 3 is the output of the regulator. This pin provides the positive 12 volt dc supply for the fan.
 

Soldering the regulator

The wires of the fan are folded under the regulator. Start with soldering the red wire of the fan first. This is the 12 volt dc wire and it connects to pin 3 of the regulator. Push a piece of heat shrink to insulate the solder joint over the wire first and the solder it to the pin.

Next com the negative wires of the fan and the new connection wire pair (both black). Strip both wires and twist them together. push over another piece of heat shrink over the wires and solder them to pin 2, the middle terminal.

The third and last wire will be the remaining red wire of the new extension wire pair. Again, push a piece of heat shrink over the wire first before soldering it to the pin 1 of the regulator.

Check your soldering and then push the heat shrink pieces over the solder joints. preferably, use a heat gun to finish off the heat shrink pieces. Now you can guide the extension wire pair to the top of the fan cover.

Putting things together

We're now ready to put things back together. There are several steps involved in this process. We have to reinstall the cooling fan and attach the newly added fan with the old fan wires coming from the Ender's electronics casing.

Installed fan

Reinstall the cooling fan

This step is pretty much the same as removing the cooling fan, but now in reverse order. Be careful to fit the cooling fan duct properly and do not damages it when fastening the screws that hold it.

The mounting holes in the duct are rather fragile and if you assert to much force fastening the screws it can easily break or snap off the mounting hole all together.

Reconnecting the fan

Before we can reconnected our newly installed fan, we must decide were we want to position the junction with the old power wires.

The most obvious place would be were they are well protected and easy to access. That would be the wire loom coming from the electronics casing.

To get good access, we need to clear the end of this loom, by clipping of the cable bundle at the end, nearest to the print head. Then we can slide back the protective cover to access the loom wires. Hold it in place with a clamp or something, like the clothespin in the picture

Cutting wires to length

Up next is cutting the wires to length. For proper installment, you must first align the new fan wire pair with the cooling fan wires, as if it were mounted already. This way we won't have a extend amount of wire left once mounted. 👉 But add approx. 5 mm extra for stripping and solder joints.

Then we need to align the new wire pair with the old wire pair in the wire loom. Now comes the catch: you will have to trim both wire pairs, but make sure that the cut in the black wires is about 15 mm apart from the cut in the red wires. The picture above should explain this hopefully a bit clearer.

The purpose for this way of cutting the wires, is to make sure it is not possible for the joints of the red and the black wires to touch each other, even if the insulation should get damaged. Thus preventing a short circuit in the fan supply.

Don’t forget: Before soldering the wires together, slide over a piece of heat shrink for insulation of the solder joint. Speaking of experience ... 😏

Mounted fan

All done !

We're almost there now. After checking the joints are firmly soldered, slide over the heat shrink and mold them over the joint using the heat gun. Make sure you don't damage the other wires or the protective sleeve.

Now we can finally mount the assembled fan cover back onto the print head. Then slide the protective back towards the end of the wire loom and fix it again wit a cable ty.

Thats it! You can now enjoy an even more silent Ender 3D Pro printer 😄.