2. Ensure the following:
• The ac breakers are in the OFF position.
• The cabinet power switch at the front of the cabinet is in the OFF position.
• The ac breakers and cabinet switches on the I/O expansion (IOX) cabinet (if one is
present) are in the OFF position.
3. If the complex has an IOX cabinet, power on this cabinet first.
IMPORTANT: The 48 V switch on the front panel must be OFF at this time.
4. Turn on the ac breakers on the PDCAs at the back of the each cabinet.
In a large complex, power on cabinets in one of the two following orders:
• 9, 8, 1, 0
• 8, 9, 0, 1
On the front and back panels, the HKP and Present LEDs illuminate (Figure C-13).
On cabinet 0, the HKP and the Present LEDs illuminate, but only the HKP LED illuminates
on cabinet 1 (the right cabinet).
Figure C-13 Front Panel Display with Housekeeping (HKP) Power and Present LEDs On
Turning On Housekeeping Power 179
