One of the VME boards (PMAC's motor board) has its own internal boot process triggered at "power on" time. So the usual boot procedure (red push button on the ioc or reboot command through the network) is not sufficient to make sure that the integral VME is correctly initialized. Thus, boot the VME by switching the AC power of the VME crate OFF and ON. The AC power switch is located in the lower part of the crate front panel.