Renkforce RF100 Fan Duct mod V1

This printer doesn't come with parts cooling stock, only with a hotend fan that will switch on at 50C. In order to make this work properly, you will need to modify your RF100 further. 

In the stock situation, the fan is wired to the terminal labeled nr. 7 in the below picture. My board did not have the green connector at nr. 6, so if that is the case, what you need to do is pick up one of these green terminal block connectors and plug that in at nr. 6. Then, you can plug the hotend fan wires in to the nr. 6 connector, and plug your new parts cooling fan wires into the nr. 7 connector.

Note: the source and drain pins of the MOSFET controlling nr.6 need to be connected for this to work. Alternatively, you can add a MOSFET to that position if you want to control the hotend fan speed, but I just let it at 100% (12V).

Then, you need to grab new firmware for your printer, so that you can tell it that you now have a parts cooling fan. I use this firmware (follow the instructions here) and what you need to do is, in Configuration_adv.h:

Replace this line:

#define E0_AUTO_FAN_PIN 9

With this line:

#define E0_AUTO_FAN_PIN -1

and in Configuration.h, replace this line:

#define FAN_PIN  -1

With this line:
#define FAN_PIN  9

Now, your hotend fan will always blow at 100% (I find it a bit much so I might stick a buck converter in between to slow it down a bit) and you can control the parts cooling fan from the firmware/slicer (with the standard M106 command).

If you need any help with this mod dont hesitate to contact me on Printables.

Floris