Ramps 1.3 with a fan not on normal mosfet

hi guys

just built my 1st ramps 1.3 board (been using a Sanguinololu before)

problem is i need to connect my fan up.

im using this for my fan (http://www.thingiverse.com/thing:22202

all the threads im reading tell people to connect there fans to pin 9 mosfet output. problem with this is i want to use a second extruder at some point and as i already have a moset setup and ready to go i see no point in this.

any ideas which pin on the ramps 1.3 i should connect to and what to set it in pins.h as?

I'd use pin9 until I had the second extruder finished, and worry about it then.

You can also connect the fan directly to 12v and a switch, and power it when needed. I find I can't have my fan turn on and off as it fluctuates the temperature too much for PID to keep up.

But you can use any spare pin to hook up a fan. From this schematic [reprap.org] pick one from AUX-4, and make the appropriate changes to the firmware.

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-Nudel
Blog with RepRap Comic

got it sorted

had a look intot he pins.h after selecting board 34 (2 extruders 1 bed) from the config.h file

by default in marlin RC3 if pin 9 is in use it uses digital pin 4

which is bottom right of the servo set of pins

only problem with ramps no header for the 12V feed for the fan so had to just put it in with the 5A 12V+ line

works a treat