Fan replacement:

So as many printer of you know, the anycubic vyper has really load built in fans. I heard cobra does too and many inexpensive, good value printers do as well. Dont quit yet, if you don't have an anycubic printer, all of the steps to replace the fans are equivalent. I hope this guide will help you replace them. 

Deciding on and buying replacement fans:

First thing you want to check is what fans are currently built in into your printer. In my case i had a 6015 (60 width and height, 15 depth) 12V 0,2A powersupply fan and a 8015 24V 0,35A motherboard fan built into my anycubic vyper. When buying noctua replacement fans you will face the problem that there is no 24V fan which is suitable for our application. As fans tend to get more silent and efficient with increasing size i decided to buy 2 noctua 9215 fans with 12V. As the motherboard fan will need 24V we need to buy some dc-dc buck converter. Its a device that convert the voltage from 12V up to 24V. I was unsure at first whether I had the confidence to do this, but don't worry it is not complicated and will learn a lot. I used AZDelivery 3 x LM2596S DC-DC converter which are high quality. (link: https://www.amazon.de/dp/B07YWLCTLK?psc=1&ref=ppx_yo2ov_dt_b_product_details). 

My recommendation for replacement fans:

2x Noctua 9225 3 or 4 pin 12V fans. I chose the Noctua NF-B9 redux-1600, because they are really silent and only need 0,12A which is below the inbuilt fans- so we are safe in our choice here. Also the redux series is a little cheaper. I have them running for over a month now and could not be more satisfied. Here is the link to amazon: https://www.amazon.de/dp/B0014I9K30?psc=1&ref=ppx_yo2ov_dt_b_product_details

You can look out to other suitable fans on their website. It is really well designed.

Stuff to buy:

-2 replacement fans

-in case you need to convert the voltage, dc-dc buck converter

Tools:

-some glue or tape

-soldering iron

-voltmeter to set the buck converter to the correct output voltage (via screw: https://www.youtube.com/watch?v=RAbTdeLU2JQ)

-recommended: cable stripper 

-small screwdriver for the buck converter screw (slot screw)

Printing the needed parts

When disassembling your printer to check what your inbuilt fans are, you have to remove both, powersupply and motherboard plate. 

I recommend this video for the anycubic vyper disassembly: https://www.youtube.com/watch?v=WaHYUNNsgkQ

The guy in the video used 2 fans which seem to not be much more silent that the inbuilt ones. But the disassembly to check your inbuilt fans is well shown.

So these metal plates have to be replaced since we will use much larger fans now. You will need to print the motherboard and psu plate. To mount the fans to the plates should print the motherboard and psu sockets. Just use regular PLA. If the temperature would rise to the melting point of PLA we would have other problem then the plates melting :). 

Also you will need to rise the printer so the fans can fit under. I designed the print feet and uploaded them here:https://makerworld.com/en/models/398548

In total you need 8 printed objects:

-PSU Plate

-PSU fan socket

-Motherboard Plate

-Motherboard socket

-4x printer feet 

You should print all parts before starting the replacement process.

Assembly: 

PSU fan:

-Open the psu case and unplug the old fan. 

-Cut the wire of the old fan. We will use the old plug. deisolate desolatethe ends of the wire. There is a red and black cable in there. 

-Cut the wire of the replacement fan. There are 3 cables in there (red, black, yellow). We wont need the yellow data cable. Just cut it or tape it off.

-Now solder the old plug together with the new fan. (solder red cable to red and black to black). More instructions: https://www.youtube.com/watch?v=NSqPHQ1zQco

-Take your fan and put it into the psu fan socket.

-Glue the socket to the printed psu plate. You can support it with tape while drying.

-Plug the new fan in (be careful to have everything well insulated and don't let cables uninsulated.

-Use some of the old screws to insert the plate into the psu. 

Motherboard fan:

The procedure is similar to the psu fan:

-remove the old fan

-cut the wires of the old fan and the new fan. 

-now we don't solder the cables together directly, instead we solder the dc-dc converter in between. At first, we want to only solder the cables of the old plug to in + and in - (red is +, black is -) because we have to set the output voltage to 12V. 

-Now we plug the dc-converter into the motherboard and put the printer on. Now we take our voltmeter and measure the output voltage between out+ and out-. We take a screwdriver and turn the screw until we have constant 12 V output voltage. 

If you don't measure a voltage, you maybe have to “start the fans” manually". You can do that by moving the printhead in one direction manually. Then the fan should turn on and the 24V will run into the converter.   

-Now we are sure our fan receives the correct voltage and we can solder the cables of the replacement fans to the buck converter.

-We will take the motherboard fan socket and insert the fan.

-Now we glue it to the motherboard plate.

-We plug the fan in and insert the buck converter into the little space i designed.

-Finally we screw the new motherboard plate in and we are done.

We can test the fans by moving the axis manually or just printing something. 

I hope this instruction helps :). Dm me for any more questions. I don't guarantee for any information given here and already excuse me for some parts that don't perfectly!