Troubleshooting the T640 SONET Clock Generators

Problem

• The green OK LED on the SCG faceplate is lit.
• The yellow FAIL LED on the SCG faceplate is not lit.
• The blue MASTER LED on the SCG faceplate indicates which SCG is the master.

• The yellow FAIL LED on the SCG faceplate is lit.
• The green OK LED on the SCG faceplate is not lit.
• A red alarm indicates that an SCG, SCG voltage sensor, or the internal clock has failed.
• A red alarm indicates that there are no SCGs online.
• A red alarm indicates that loss of signal has occurred from an external clocking device connected to the RJ-48 Aor B port.
• A yellow alarm indicates that an SCG is not online in a router with redundant SCGs or that an SCG has been removed..
• A yellow alarm indicates that a temperature sensor has failed.

Solution

1. Check the LEDs on the faceplate of each SCG and on the craft interface.
2. Use the CLI to check for alarms.
   • Standalone router—Issue the show chassis alarms command to view the alarms.
   • Router in a routing matrix—Issue the show chassis alarms lcc lcc-number command to view the alarms.

In Table 1, the text in the column labeled ”LCD Message” appears in the display of the craft interface. The text in the column labeled “CLI Message” appears in the output from the show chassis alarms command.