I have just acquired this machine and the hotend will not heat. The hotend heat cartridge is not open and I believe the control board is the issue. So without purchasing unassay parts, I have ohmed out the cartridge and is is not open, tested for output voltage on the control board HEAT1 but got 0. My question is can I used HEAT2? I have some experience in Marlin and can re-assign the pins, But is the Marlin firmware the proper firmware to use on this machine, as I can not find UM firmware that is in a base code, I can only find the HEX versions. Any help would be greatly welcomed..