ADTRAN 25 manual Maintenance Strategy

MAINTENANCE

MAINTENANCE STRATEGY

Fault isolation is the cornerstone of the System 25 maintenance strategy. Maintenance activity isolates faults to one (or more) repairable or replaceable maintenance units. Equipment should be tested in the following order:

1.Terminal equipment

2.Station wiring

3.Port circuit packs (CPs)

4.Common control circuitry

5.Power supply and cabinet

6.Backplane.

The first fault isolation step attempts to reproduce the fault, whether it is system-detected or user-reported. A fault that can be reproduced is more easily diagnosed and corrected.

Figure 4-1presents a practical approach in responding to system troubles. If the maintenance technician is sent to a System 25 site in response to a trouble report, the maintenance activity will probably consist of isolating and replacing one or more faulty units of equipment. However, multiple faults recorded in the Error Log and user-reported troubles may require more investigation and analysis’.

When the limits of trouble-clearing analysis are reached and the trouble is still not cleared, the maintenance technician must escalate the problem to a higher level of technical support. Problems should be escalated to the National Service Assistance Center (NSAC) in Denver, Colorado. The telephone number is 1-800-628-2888.

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