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Fault detection and locating
553-2601-500A
Standard 2.0
December 1994
Procedure 3
PE2, PE3, PE4, or PE5 breaker trips
Step
Action
Verification
1
Reset breaker.
If breaker does not trip, fault is cleared.
2
Check for extinguished LED on QPC706
pack associated with tripped breaker and
replace pack. Reset breaker.
If breaker does not trip, fault is cleared.
3
Unseat all circuit packs on the shelf
except the QPC706 pack. Reset breaker.
If breaker trips, replace power cabling to
shelf at rear of cabinet. If breaker still trips
when reset, replace the QUX20 unit.
4
Insert circuits one at a time until
breaker trips.
Last circuit pack inserted is defective.
Replace.
Procedure 4
FN fuse operates or FN LED is extinguished
Step
Action
Verification
1
Remove rear EMI shields (if equipped)
and check connector J7 at rear of QUAA3
unit. Connection should be secure.
2
Ensure that FN fuses are not blown or
defective.
If fuse blows when replaced, replace fan
units one at a time. If fault persists,
replace cabling to cooling units at rear of
cabinet followed by QUX19 unit.
3
If fuses are good and FN LED is not lit,
replace QUAA3 unit.
Note:
When not equipped with cooling units, the cable from the QUX19 unit should be connected to J7 on
the QUAA3 unit. When cooling units are equipped, J7 is connected to the cabinet wiring leading to the
cooling units.
