SYSTEM MAINTENANCE OUTLINE

The following is an example where the fault was recovered after the replacement of circuit cards:

START

Set the 1st circuit card back into its mounting slot

If the fault recurs: Replace the circuit card.

Set the 2nd circuit card back into its mounting slot

If the fault recurs: Replace the circuit card.

Set the 3rd circuit card back into its mounting slot

If the fault recurs: Replace the circuit card.

If a circuit card is found to be faulty, send the faulty circuit card for repair.

The fault may be a temporary one, or due to poor contact of the circuit card. Observe the situation for a while.

END

(8)When a fault recovery is completed, use the RALM command to clear all the alarm indications and registered system messages. If required, restore temporary cross connections and transient data for testing to the original ones.

3.2How to Follow Diagnostic Procedure/Fault Repair Procedure

(a)Diagnostic Work

A fault diagnostic procedure by system message is explained in the “TREE” format on an individual system message basis.

Proceed with judgment as to whether the fault status coincides with the indicated status, following the sequence beginning from START.

How to proceed with the diagnosis work is explained in Figure 2-24.

STEP 1 Determine whether the fault coincides with the fault status (1) in Figure 2-24.

STEP 2 If the fault status does coincide, the fault is indicated by (2). Repair the fault by referring to the relevant section in Chapter 5. Otherwise, proceed to (3).

STEP 3 Perform the work indicated by (3). The result of the work (3) is broken down as indicated by

(4).

STEP 4 Determine whether the result of work (3) coincides with the status indicated by (5). If so, the fault(s) is/are indicated either by (6) or by (7). If not, proceed to the next Step.

CHAPTER 2

NDA-24300

Page 30

Issue 1

Page 57
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NEC NDA-24300 manual Start, End, How to Follow Diagnostic Procedure/Fault Repair Procedure