User's Manual

ADCP-75-348 • Issue 1 • 04/2008

Page 30

Figure 22. Power Supply Replacement

9. Turn power switch to the ON position.

10. Notify the NOC or alarm monitoring system operator that the system is back in operation.

7.3 System Card Replacement Procedure

System Card can be replaced without disrupting service. If the EXT REF is being used

communications to other HU’s will be disrupted.

1. Before working on the HU or handling a System Card, slip on an Electro-Static Discharge

(ESD) wrist strap and connect the ground wire to an earth ground source. Wear the ESD

wrist strap while completing each section of the fan installation procedure.

2. Notify the NOC or alarm monitoring system operator that the System Card is being

replaced.

3. If used, disconnect EXT REF cables from the front of the System Card.

4. Remove alarm plug from the front of the System Card by pressing on the lock tabs.

5. Loosen the two thumb screws that secure the System Card to the front of the HU

enclosure. See

Figure 23.

Warning: Electronic components can be damaged by static electrical discharge. To prevent

ESD damage, always wear an ESD wrist strap when working on the HU and when handling

electronic components.

22400-A