@3mm said in Fan1 disappeared, V6 hotend temp problem, loss of EtherNet conn: @dc42 Ok, but what about the 11.5Vdc reference issue? What does that effect directly...its important enough to display its value on the DWC? Why is it reading low? If its not affecting anything, why care? Its either a SW issue or the chip is out of spec. I don't understand why that reading is low. The tolerance on that reading is +/-5%, but that include the 3% tolerance of the 3.3V reference. If the 3.3V rail is accurate as your meter suggests, the reading should be within +/-2%. The accuracy depends on the ADC accuracy (which is normally very good once the firmware has run auto calibration on it) and the values of R60 and R61. 2nd Problem: EtherNet Disconnecting. Ethernet disconnection issues are usually caused by either a bad Ethernet cable or an IP address conflict. Are you using a static IP address assignment, or DHCP? Which firmware version are you running?