Note: On XBB2 (7900) systems, removing a single controller disconnects one of the AC power supplies and causes the processor to overheat if one controller is pulled from the system for more than 15 mi...Note: On XBB2 (7900) systems, removing a single controller disconnects one of the AC power supplies and causes the processor to overheat if one controller is pulled from the system for more than 15 minutes. Symptomatically, the controller that fails to ACS or has a submodel ID mismatch is typically going to be marked offline automatically by the surviving controller, and report entries such as the following in the Recovery Guru: