Avaya MCC1 Maintenance Procedures page 272

Packet and serial bus maintenance
G650 Serial Bus fault detection and isolation
Figure 80: TDM/LAN bus connection to the Serial Bus
Serial Bus faults can be caused by
• A defective circuit pack connected to the inserted into one of the G650 slots.
• Bent pins on the G650 backplane.
• Defective TDM/LAN bus cables.
It is possible that a circuit pack can cause a Serial Bus fault and still exhibit trouble-free operation. For
example, insertions of any circuit pack into a G650 slot might bend the backplane pins and short two
leads together. Or a circuit pack that doesn't use the Serial Bus could still have an on-board short of one
of the Serial Bus leads. Since the Serial Bus is a shared resource that each circuit pack and power supply
has access to, identification of the cause of a Serial Bus fault can be difficult.
!
Since the Serial Bus fault isolation procedure involves removing circuit packs and possibly
disconnecting entire carriers, the procedure is extremely destructive to the port network that is
being tested. If possible, arrange to perform this procedure at a time when traffic is minimal.
As circuit packs are removed or entire carriers are disconnected, any active calls terminating on those
circuit packs or carriers are dropped. If you have any hints about a particular circuit pack that might be
causing the Serial Bus problem
• Investigate those suspect circuit packs before performing either procedure. For example, look at
any circuit packs that were inserted into the PN just before the Serial bus problem appeared.
• Examine which power supplies that the system is unable to show with the
power-supply
!
When straightening or replacing backplane pins in a carrier, power to that carrier must be shut off.
Failure to follow this procedure may result in damage to circuit packs and power supplies and can
be hazardous to the technician.
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cabinet and concentrate on those carriers and their cabling.
WARNING:
list configuration
Maintenance Procedures
December 2003