Maintenance; Tools And Materials; Fault Detection And Alarm Reporting - ADC DIGIVANCE User Manual

ADCP-75-114 • Issue C • June 2001

4 MAINTENANCE

This section explains the alarm reporting system, provides a method for isolating and
troubleshooting faults, and provides procedures for replacing the cooling fan.
The RIU requires no regular maintenance to insure continuous and satisfactory operation.
Maintenance, as it applies to the RIU, primarily involves diagnosing and correcting service
problems as they occur. When an alarm is reported, it will be necessary to follow a systematic
troubleshooting procedure to locate the problem. Once the source of the problem is isolated,
the appropriate corrective action can be taken to resolve the problem. The only component that
can be replaced is the cooling fan. The failure of any other component within the RIU requires
replacement of the RIU.

4.1 Tools and Materials

The following tools and materials are required in order to complete the procedures in this
section:
•
ESD wrist strap
•
Small size flat-bladed screwdriver
•
TORX screwdriver (T10)

4.2 Fault Detection and Alarm Reporting

Detection of a fault by the RIU generates an external alarm response. An ALARM LED
indicator is provided on the RIU front panel to visually indicate when a fault is detected. In
addition, normally open (NO) and normally closed (NC) dry alarm contacts are provided to
report minor and major alarms to an external alarm system. A minor alarm is defined as a
high temperature condition. A major alarm is defined as a power amplifier over/undercurrent
condition.
When the RIU alarm contacts are connected to an external alarm system, detection of a fault
will generate an alarm at the Network Operations Center (NOC). Whenever a problem is
reported, refer to Table 5 to isolate and correct the fault.
Alarm Type:
ALARM Indicator: Yellow:
POSSIBLE CAUSE
1. Air intake or exhaust openings to RIU
chassis blocked.
2. Ambient temperature > 58º C/136º F.
3. Faulty fan.
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© 2001, ADC Telecommunications, Inc.
Table 5. Fault Isolation and Troubleshooting
Minor
CORRECTIVE ACTION/COMMENTS
1. Remove cause of air-flow blockage.
2. Reduce ambient temperature.
3. Replace fan (see Subsection 4.3).
Continued