![Rat Rig Community [Unofficial]](https://cdn.discordapp.com/icons/582187371529764864/08375bea6b5b9088b6d4cfc2b6e25fba.webp?size=48){kind=icon}
Issues with IDEX 4028 part cooling fans quickly changing speeds
Hello all,
I have some weird issues with my 4028 12v Part cooling fans connected to my Octopus MAX EZ board. Im in the process of setting up my VC4 IDEX, everything worked fine in CoreXY and Hybrid but since putting in a second toolhead I'm now seeing some issues. Both fans are connected to either the 12v pin on the 2 pin fan port OR the 12v pin on the 4 pin fan port, both work independently (only 1 fan connected to power at a time) and I can ramp the speed up from 0 to 100 without issue. As soon as I introduce the second fan I can only gradually increase the speed of the fans, as soon as 1 fan has a quick increase in speed BOTH fans will stop working. You try to adjust the speed on the sliders and nothing happens, the only way to the fans working again is to reboot klipper.
I've tried a different combination of 12v 4028 fans (Nidec, Sanyo & Delta) but they all act the same way. I've tried an independant 12v PSU to connect the fans and that didn't work. Both fan are connected as per this guide: https://os.ratrig.com/docs/guides/4028/ using the gnd on the heater ports. Any help/suggestions would be very much appreciated.
I have some weird issues with my 4028 12v Part cooling fans connected to my Octopus MAX EZ board. Im in the process of setting up my VC4 IDEX, everything worked fine in CoreXY and Hybrid but since putting in a second toolhead I'm now seeing some issues. Both fans are connected to either the 12v pin on the 2 pin fan port OR the 12v pin on the 4 pin fan port, both work independently (only 1 fan connected to power at a time) and I can ramp the speed up from 0 to 100 without issue. As soon as I introduce the second fan I can only gradually increase the speed of the fans, as soon as 1 fan has a quick increase in speed BOTH fans will stop working. You try to adjust the speed on the sliders and nothing happens, the only way to the fans working again is to reboot klipper.
I've tried a different combination of 12v 4028 fans (Nidec, Sanyo & Delta) but they all act the same way. I've tried an independant 12v PSU to connect the fans and that didn't work. Both fan are connected as per this guide: https://os.ratrig.com/docs/guides/4028/ using the gnd on the heater ports. Any help/suggestions would be very much appreciated.
4028 server fans are becoming a popular option for part cooling because of their light weight and great pressure and flow rates. In this guide we'll go over how to connect one and use it for part cooling. 4-pin fans usually aren't used in 3d printers, and many boards only provide 2-pin ports, but fear not! There's always a way.
![Rat Rig Community [Unofficial] banner](https://cdn.discordapp.com/banners/582187371529764864/4ee3e42e227d6aac26f048a3e69d5924.webp?size=480)
![Rat Rig Community [Unofficial]](https://cdn.discordapp.com/icons/582187371529764864/08375bea6b5b9088b6d4cfc2b6e25fba.webp?size=16){kind=icon}