Cisco 12012 Replacement Instructions Manual page 13

Before proceeding to the next step, verify that the source DC circuit breaker servicing the
Caution
DC power supply you are removing is in the OFF position. Also verify that the power switch on the
DC-input power supply is OFF (O). As an additional check, measure the voltages across the leads
attached to the power supply you have removed. All readings should be zero volts.
Remove the outer nut and washer from each terminal and disconnect the source DC
Step 9
power cable leads from the power supply lugs in the following order: negative (–),
positive (+), and ground. (Refer to Figure 8.)
Figure 8 Disconnecting the DC-Input Power Supply
Circuit breaker
alarm terminal
block
Pull the DC power cable leads down through the power supply handle and set the power
Step 10
cable aside.
As an added precaution, we strongly recommend that you place tape over the exposed
Caution
metal terminals on the power cable to prevent accidental contact between the leads or the leads and
ground.
If leads are attached to the power supply circuit breaker external alarm terminal block,
Step 11
record on a piece of paper which terminals the leads are attached to for later connection.
Disconnect the leads attached to the circuit breaker alarm terminal block. (Some sites
Step 12
might not have an external alarm system for the power supply circuit breaker.)
Cisco 12012 Gigabit Switch Router DC-Input Power Supply Replacement Instructions
– + Ground
Source DC
power cable
Removing and Replacing a DC-Input Power Supply
13