Avaya S8700 Maintenance Manual page 183

Isolating and Repairing Packet-Bus Faults
3. If the pins are bent:
a. Power down the carrier if it is not already.
b. Straighten or replace the pins.
c. Insert the same circuit pack.
d. Restore power to the carrier.
4. If the backplane pins are not bent, reinsert or replace the circuit pack.
5. Determine whether the packet-bus fault has been resolved. If so, you are
finished.
If not, do the following:
a. If the old circuit pack was reinserted in
b. If the circuit pack was replaced with a new one, proceed with
6. Repeat this procedure for the other Tone-Clock. If both have already been
checked, continue with
7. If every EPN control circuit pack has been checked and the problem is still
not resolved, continue with
Procedure 4: Isolating Failures
Procedure 4 is used when the preceding procedures fail or when open leads are
present. It is helpful in identifying multiple circuit-pack faults and carrier hardware
faults. It attempts to isolate the failure to a particular set of carriers and checks
only the circuit packs in those carriers.
In Procedure 4, the TDM/LAN cable assemblies and TDM/LAN terminating
resistors are replaced. If this action does not resolve the packet-bus fault, the
carriers are reconfigured by moving the terminating resistors on the carrier
backplanes in such a manner that certain carriers are disconnected from the bus.
To terminate the packet bus at the end of a particular carrier, unplug the cable that
connects the carrier to the next carrier and replace the cable with a terminating
resistor (see
modified with this procedure, circuit packs that are essential to system operation
(and the TN771D Maintenance/Test circuit pack in stand-alone mode) must still be
connected to the new 'shortened' packet and TDM buses.
!
DANGER:
Power must be removed from the entire port network before any cables or
terminators are removed. Failure to do so can cause damage to circuit
packs and power supplies, and can be hazardous to the technician.
NOTE:
Circuit packs in carriers that are not part of the shortened bus are not
inserted. As a result, these circuit packs are not alarmed. For now, ignore
555-233-143
pack, and repeat Procedure 3 starting at
step 7.
Procedure 4: Isolating
Figure 4-47 on page 4-110). When the length of the packet bus is
step 4, replace the circuit
step 2.
step
Failures.
Issue 1 May 2002 4-109
6.