dlmorgan999

Thanks for the quick response! I didn't explain myself very well. I already had the full Marlin source specifically configured for my UM2 and I knew that the Amedee build didn't support that, so I looked at the source in the Github repository to determine the changes required to support that pin (I just replaced setExtruderAutoFanState in temperature.cpp, and changed EXTRUDER_0_AUTO_FAN_PIN to 255 ) and recompiled. Maybe I made a mistake or missed something, but after making those changes, the output still doesn't work (although the voltage does change right at the specified hot end temperature). The voltage readings are a bit confusing to me so that's why I wondered if there was a hardware issue. Thanks for the pointer to the other thread though. I think I'll post something over there as well.

I'm in the final stages of building an Ultimaker 2 Extended clone (from a project on Thingiverse). I've searched the forum and read various threads on fan issues (seems to be a common problem) but my issue is slightly different. I'm using an E3D V6 hotend, and was planning to use the fixed (non-PWM) 5V output (J34) to power the fan. First I tried it with the regular Ultimaker 2 Marlin firmware and that didn't work. Then I learned about the Amedee builder, but I already had firmware mostly configured the way I want, so I took the changes from that firmware and applied them to mine to enable that connector but it still isn't working. One odd thing I noticed is that when the fan should be off (hotend temperature below 40c), I measure 4.9v and when it should be on, I measure 3.6v. The fans never come on in either case. I tested the fans with an external power supply and they work fine. I also checked my cable with an ohm and volt meter and it's good. I haven't yet gotten the viewer for the schematic files, so I don't know, but I assume that since this is switchable on the 2.1.4 board that there must be a transistor involved. When I first had the fans connected, I unfortunately had the polarity reversed. Did I perhaps blow out a transistor? I don't know what to make of the voltage readings.