The McIntosh MCD12000 experiencing multiple power cycles with clicks and tube activation may indicate a fault in the power supply or internal circuitry. I suggest you contact McIntosh customer support.
Users have reported that the McIntosh MCD12000 can be finicky when connecting to Roon, sometimes taking hours to appear or not showing up at all. If problems persist, please contact McIntosh support for further assistance, as it could indicate a compatibility issue with the Roon setup or the MCD12000 itself.