During the printer commissioning I realized, that the Rumba does not power the hotend fan (have a BB Hybrid with only one printhead). Rising the temperature higher then 40°C turns on the LED "Fan1" on the Rumba, but the fan does not run. When I put 12V to the hotend fan cable, then the fan works. So the cabeling is fine; what else could be the reason for such a problem? My Voltmeter tells me as well, that there will no power at the screw terminals "Fan1"...
... there is no power at the pins - that's the place where I plug the single fan. Of course with the correct polarity.
Yes, as I already mentioned: The LED for Fan1 turns on, but no voltage at the terminal screws or the pins...