Technical data

The orange I symbol indicates an intake unit. This unit pulls air in from the nonport side of the switch
and exhausts it out the port side. This is also called back-to-front airflow or reverse airflow. This
symbol should appear on FRUs with part numbers ending with -R .
The chassisShow command indicates "reverse" airflow.
If one fan fails, the remaining fans go to high speed to maintain proper cooling until the failed fan is
replaced.
If a mismatched power supply or fan is installed by mistake, a critical error message is sent to the
console. The message will be similar to the following:
CRITICAL HIL-1611 MISMATCH in PSU/FAN Air Flow direction. Replace PSU with
fan air flows in same direction. System will be shut down in 2 minutes.
Power supply removal and replacement
The switch has two power supplies. The Fabric OS identifies the power supplies from left to right on
the nonport side as power supply #2 and power supply #1.
NOTE
Disassembling any part of the power supply voids the part warranty and regulatory certifications.
There are no user-serviceable parts inside the power supply. Because the cooling system relies on
pressurized air, do not leave either of the power supply slots empty longer than two minutes while the
switch is operating. If a power supply fails, leave it in the switch until it can be replaced. Maintain both
power supplies in operational condition to provide redundancy.
Refer to LEDs on the nonport side of the switch on page 34 for the power supply status LED colors,
behaviors, and actions required, if any.
Determining the need to replace a power supply
Use one of the following methods to determine the status of the power supplies:
• Check the power supply AC status and DC status LEDs. Both should be green (refer to LEDs on
the nonport side of the switch on page 34). If the DC status LED is amber, there is no power on the
cord.
• In Web Tools, click the Power Status icon.
• At the command prompt, enter the psShow command to display power supply status:
sb_70:admin> psshow
Power Supply #1 is OK
Airflow Direction : Portside Exhaust (Reverse)
Power Supply #2 is OK
Airflow Direction : Portside Exhaust (Reverse)
DANGER
Disconnect the power cord from all power sources to completely remove power from the
device.
Power supply removal and replacement
42 Brocade 7840 Extension Switch Hardware Reference Manual
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