NEC SV8500 Operation And Maintenance Manual - page 640
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CHAPTER 5
Operation Procedure for System with PIR
Perform the following procedure to confirm the cause of the DC-48V fuse blown fault (PIR).
Start
Visual check: No pin contacting
or backboard melting?
OPE Lamps (green) of
LC/TRK/NCU cards remain lit?
Make sure in which module
the fuse has blown
No
1. Turn ON (UP) the MB key
on the circuit card.
2. Remove the card from the PIR.
3. Replace the fuse with a new one.
Turn ON (UP) the MB
keys on the whole circuit
cards, and remove them from
the PIR. (Only PWR cards
are inside the PIR)
Turn ON (UP) the MB
keys on the whole circuit
cards, and remove them from
the PIR. (Only PWR cards
are inside the PIR)
The replaced fuse
is blown again?
No
No
No
No
Fault of circuit card that
accompanied the fuse blown.
Perform system initialization
after inserting all removed cards.
Fault of circuit card
that was removed
Replace the blown fuse
with a new one.
Replace the blown fuse
with a new one.
Yes
Yes
Yes
Insert the removed cards
one by one (into the PIR).
Is there any fuse blowing?
The replaced fuse
is blown again?
The fuse is still blown?
There is a short circuit on the
backboard of the PIR.
Fault of PWR card.
Replace the PWR card
Yes
Yes
No
Fault of circuit card that
accompanied the fuse blown.
Perform system initialization
after inserting all removed cards.
Yes
Insert the removed cards
one by one (into the PIR).
Is any fuse blown?