Using Fan2 output

[hmanvel]

I've searched this forum and Rambo forums and Repetier forums, still cannot get a complete grasp on how to do this. I want to enable the fan2 output in my Rambo, to power an extruder cooling fan. Can somebody step me through this? I know I have to make some new definitions etc., I found some references to pins.h in the Repetier, mine doesn't even have pins.h. Any advice appreciated!

[geneb]

By "extruder" are you referring to the extruder stepper motor itself?

Note that any fan pin changes are going to be done in Configuration.h, not pins.h

g.

[hmanvel]

Right, the stepper motor. It gets hot enough that printing PLA it can quit feeding due to the filament partially melting in the mechanism. I didn't know about that pins.h, glad to hear it isnt required. Still hoping someone can step me through how to set up the configuration.h, and then what G-code to control it.

[geneb]

Well there IS a pins.h file - it's used by the firmware. However, that's not where fan pins are assigned.

The problem you've got is probably due to a motor that's being driven at too high a current.

Can you attach a copy of your Configuration.h file to a reply for me? I'd like to see where you've got the extruder motor current set.

tnx.

g.

[hmanvel]

Here it is, thanks. FYI I piggybacked the fan off of fan wires with the original hot end, then upgraded to the better hot end and couldn't access the proper wires, so figured I would drive it off of the Fan 2 output, after all it's there to power a fan? It did a good job of cooling the drive, was a CPU cooler off an old computer.

[geneb]

It doesn't look to me like you're over-driving the extruder stepper. What you might want to do is just piggy back the extruder fan off of the output that drives the cold-section fan on the hot end.

g.

[hmanvel]

Thanks for looking. That is the way I had it wired with the original hot end, but now with the new one (HES280? Not sure) there's a wiring harness and I was hoping not to break into it. Oh well might have to.

[geneb]

Oh, you'd have to do that anyway - there's no wires in there that are extra or would support the fan2 output.

g.