User's Manual

User Instructions Section 5877
Spec. No. 582140000 (Models 802NLDB, 802NLEB and 802NL-B) Issue AQ, January 15, 2013
Chapter 6. System Troubleshooting and Repair Page 6-11
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MCA Circuit Card Replacement
The MCA circuit card is installed in the Primary Power/Distribution Bay and Primary
Power Only Bay. Router circuit cards are installed in the Secondary Power/Distribution
Bays, Secondary Power Only Bays, and Distribution Only Bays.
Note: Refer to Figure 6-2 as this procedure is performed.
Procedure
1) Observe the admonishments presented at the beginning of this chapter, and
those encountered in this procedure.
2) 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.
3) Replacing the MCA circuit card WILL result in all MCA settings being returned to
their factory default values. In Table 6-2 and Table 6-3, either manually record
all existing MCA settings or record the required settings for your site from your
company's DC Plant Set Points specifications (standards).
Note: The MCA configuration can be saved by downloading the configuration
using the LMS Monitoring System (if installed).
Refer to the MCA Menu Tree (Section 5886) and Chapter 2. Navigating the MCA
to manually record MCA settings. The MCA Menu Tree is provided in the
separate INSTALLATION MANUAL and the CD CARRIER MANUAL (it is also
provided on the CD).
4) Open the bay's front door to access the MCA circuit card mounting position.
Warning: Damage to the MCA circuit card may result if the next step is not
followed.
5) Connect an approved grounding strap to your wrist. Attach the other end to a
suitable ground.
6) Remove fuse F3 that supplies input power to the MCA circuit card. Refer to
Figure 6-7 for location.
7) With an external voltmeter, verify plant voltage is correct (MCA is powered down
at this point).
8) Remove any network cables from the circuit card, noting their locations for re-
assembly.
9) Remove the alarm cable connector TB1 from the circuit card. Note that terminal
block TB1 consists of two pieces snapped together. The two pieces can be
separated by first loosening the two screws; then gently pulling the one half from
the other.
10) Loosen the circuit card retaining screw.
11) Remove the circuit card.
12) Set the switches of S1 on the replacement circuit card to match the settings of
the removed circuit card.
13) Slide the replacement circuit card into its mounting location, ensuring the rear
edge connector is firmly seated.
14) Secure the circuit card by tightening the circuit card retaining screw .