There are sensor targets which enable you to display the voltage levels and alarm states on the motherboard.
-> show -d properties voltage_sensor_target
where voltage_sensor_target is from the table in Board Level Voltages.
For example, to display the voltage of the main 1.8V source:
-> show -d properties /SYS/MB/V_1.8V /SYS/MB/V_1.8V Properties: type = Voltage ipmi_name = MB/V_1.8V class = Threshold Sensor value = 1.785 Volts upper_nonrecov_threshold = 1.979 Volts upper_critical_threshold = 1.940 Volts upper_noncritical_threshold = 1.891 Volts lower_noncritical_threshold = 1.697 Volts lower_critical_threshold = 1.639 Volts lower_nonrecov_threshold = 1.591 Volts alarm_status = cleared ->