Additional fan on Melzi controller not working

Hi folks

I have a reprappro Mendel working fine so far.. to get better results I bought an aditional cooling fan hoping that could be connected to Melzi board (on specific entry for that.. i guess).
So, when I connect this additional fan on the same entry of the extruder fan, it works fine... but when I connect it to the specific Melzi board entry for "additional fan" nothing happens..

Does anyone have any idea what I'm doing wrong? =/

Thks
Jose

How are you testing the fan? It wont run until it's told to, wich you can do by sending M106, or using the fan controls in pronterface/repetier host.

I'm sending M106 to start and M107 to stop.. just to confirm, I check.. when ON (M106) 12,27 Volts and when off 0 Volts.. I tried with 3 diferent cooler fans (2 old stuff and 1 pretty new.. bought one hour ago)... and nothing.. =/

Did you find a solution to this ?

I have the same problem.

Check the polarity of the fan connections - fans need 12V going through the the correct way. M106 needs to be used with a speed value, ie send M106 S255 for full speed; see [reprap.org]

Ian
RepRapPro tech support

I had the same problem and it was due to polarity. Although these fans use DC, they do need their plus lead connected to positive and their negative lead to negative.

Harvey

I have the same problem, it seems my part fan never runs, how to make it start ? thanks