Packet Bus Fault Isolation and Correction
555-233-123
9-28 Issue 4 May 2002
Procedure 2
Procedure 2 removes and reinserts port circuit packs (those in the purple slots)
one or several at a time. Use Procedure 2 for each port circuit pack in the port
network until either (1) the problem is resolved or (2) there are no more circuit
packs in the port network.
NOTE:
This procedure should also be used for the TN570 Expansion Interface
circuit pack in a standard system. For a High or Critical Reliability system,
refer to Procedure 3 for the Expansion Interface circuit pack. Also, refer to
Procedure 3 for the TN768 or TN780 Tone-Clock circuit pack in a switch with
a High or Critical Reliability system.
!
CAUTION:
The Expansion Interface circuit pack should be the last one checked in this
procedure, since removing this circuit pack disconnects its EPN. The
Tone-Clock circuit pack should be the next-to-last one checked. In addition,
the TN771 must be reseated after the Tone-Clock is reinstalled.
If the Packet Bus problem is present when the circuit pack is inserted, but is
resolved when the circuit pack is removed, either the circuit pack or the backplane
pins in that slot caused the problem. If the backplane pins are intact, replace the
circuit pack.
NOTE:
In a multiple failure situation, the circuit pack could be one cause of the
Packet Bus problem. However, there could also be other failures that are
causing Packet Bus faults.
In Procedure 2, an option of working either with one circuit pack at a time or with
multiple circuit packs simultaneously is available. In view of this, determine the
level of service interruption to be allowed during this procedure. If causing a
disruption to all users in the port network is deemed permissible, large groups of
circuit packs should be worked with. This option allows faster job completion.
However, if large service disruptions are to be avoided, work with one circuit pack
at a time. This option is slower, but it disrupts only the users of a single circuit
pack.
!
CAUTION:
If the TN771 Standalone mode does NOT indicate Packet Bus faults,
perform Procedure 2 for ONLY the port (purple) slot Packet circuit packs
listed in Table 9-1 on page 9-27. Also, problems with the backplane pins
need not be checked for. Determining if the problem is resolved by removing
circuit packs is sufficient.
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