User Instructions UM582127000
Spec. No. 582127000 (Model 721NPBB) Issue AC, January 2, 2013
Chapter 4. Troubleshooting and Repair Page 45
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SM-DU+ and Shunt Interface Assembly Replacement
Procedure
1) Performing this procedure may activate external alarms. Do one of the following.
If possible, disable these alarms. If these alarms cannot be easily disabled,
notify the appropriate personnel to disregard any future alarms associated with
this system while the procedure is being performed.
Danger: Performing the next steps exposes service personnel to battery
potential. Exercise extreme caution not to inadvertently contact or
have any tool inadvertently contact any energized electrical
termination.
2) Open the distribution cabinet’s front door by turning the latch in the
counterclockwise position.
Warning: Damage to the circuit card may result if the next step is not followed.
3) Connect an approved grounding strap to your wrist. Attach the other end to a
suitable ground.
4) Carefully label the wires connected to the shunt input terminal blocks on circuit
card. These wires must be connected to the same terminals on the replacement
circuit card. Refer to Figure 4-13.
5) Carefully label the connectors plugged into the circuit card. These connectors
must be plugged into the same connectors on the replacement circuit card.
Refer to Figure 4-13.
Danger: In the next step, external wiring may be energized from an external
source. DO NOT allow bare wire ends to contact any grounded or
energized object.
6) Remove the external wiring from the shunt input terminal blocks. DO NOT allow
the bare wire end to contact any grounded or energized object. Isolate the wire
end with electrical tape. Repeat for each wire to be removed.
7) Unplug all connectors plugged into the circuit card.
8) Remove the screw securing the SM-DU+ and Shunt Interface Assembly to the
bottom of the distribution cabinet, and remove the assembly.
9) SM-DU+: In this step, ensure you do not intermix the old and replacement circuit
cards. Set the switches on the replacement circuit card to the same settings as
the old circuit card. Switch settings are documented in CHAPTER 3. SETTING
JUMPERS AND SWITCH OPTIONS of the Power System Installation
Instructions (IM582127000).
10) Slide the replacement SM-DU+ and Shunt Interface Assembly into the mounting
position inside the distribution cabinet, and secure with the screw removed from
the old assembly.
11) Plug all connectors removed from the old circuit card into the same position on
the replacement circuit card.
Danger: In the next step, external alarm wiring may be energized from an
external source. DO NOT allow bare wire ends to contact any
grounded or energized object.
12) Reconnect the external wiring to the correct terminals on the shunt input terminal
blocks. First remove the electrical tape that was applied to the bare wire end in a
previous step. DO NOT allow the bare wire end to contact any grounded or
energized object. After securing the wire, gently tug on the wire to ensure that it