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4.5 Fault Isolation and Troubleshooting
The symptoms and corresponding procedures listed in Table 4-3 enable
the user to identify, isolate, and correct faults in accordance with the
knowledgeable tools and replacement parts available.
These service instructions are for use by qualified personnel only.
To avoid electric shock, do not perform any servicing other than that
contained in the operating instructions unless you are qualified to do so.
Table 4-3. Fault Isolation and Troubleshooting.
Symptom
All front-panel indicators are OFF.
Red LOCAL SYNC LOSS is ON
Red REMOTE SYNC LOSS is ON
WARNING
Action
(a) Check that power is supplied to the unit.
(b) Check the fuse inside the AC receptacle
on the rear panel and replace it with a new
one.
(c) Replace unit. The fault is probably in the
unit's power-supply circuits.
(a) Perform LLB. Yellow TEST indicator
should light and LOCAL SYNC LOSS
should go OFF. If not, replace the local unit.
Otherwise, proceed to step (b).
(b) Perform local RLB. Yellow TEST
indicator should light and LOCAL SYNC
LOSS should go OFF. In that case, replace
the remote unit. Otherwise, proceed to
step (c).
(c) Perform steps (a) and (b) at the remote
site. If the fault is still not located, replace
both units one at a time. If the problem
remains, the main-channel link between
the units is probably defective and should
be checked.
Perform all the tests as in the case of
LOCAL SYNC LOSS, starting at the remote
site.
LOCAL MUX-6
25
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