NEC Univerge SV8500 Operation And Maintenance Manual page 59

• 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 1-9.
STEP 1 Determine whether the fault coincides with the fault status (1) in Figure 1-9.
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 4. 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.
STEP 5 Perform the work indicated by (8), and if the result of the work is the same as the status indicat-
ed, the fault is indicated by (9). If the fault repair work indicated by (9) affects another normal
line, recheck the work as indicated by (10).
(b) Fault Repair Procedure
A fault repair procedure is explained by means of TREE format in Chapter 4. The following explains
how to follow the TREE format and proceed with designated work. See Figure 1-10.
• Begin from START and proceed with the necessary repair work following the sequence.
• When a faulty circuit card (or circuit cards) is suspected, replace the faulty circuit card with a spare
in accordance with the work procedure pertaining to that specific circuit card.
STEP 6 Replace the circuit card indicated by (A) with a spare and check it. Perform the detailed work
as per (B). If the fault status is beyond repair, proceed to the next step.
STEP 7 If the range of the fault or the system configuration is as indicated by (C), perform a check as
indicated by (D). If the fault status is beyond repair, proceed to the next step.
STEP 8 Replace the circuit card indicated by (E) with a spare and check it. The detailed procedure indi-
cated by (G) varies with the system configuration indicated by (F).
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CHAPTER 1 General