Hardware Troubleshooting 5-13
Troubleshooting the Dial Shelf Processor Subsystem
—If power is supplied to the router shelf but the enabled LED remains off, the system has
detected a hardware failure. You need to replac e the interconnect port adapter.
•Is the link LED on?
The link LED indicates an active connection to the dia l shelf. Thi s LED lights when t he dial s helf
interconnect port adapter is receiving a carrier signal from the dial shelf.
—If the link LED remains off, check the dial shelf interconnect cable connection and tighten
the jack screws at both ends of the cable.
—If the connection is good but the link LED remains off, proceed to the section
“Troubleshooting the Dial Shelf Controller Card.”
Troubleshooting the Dial Shelf Processor Subsys tem
The following sections describe troubleshooting procedures for the DSC card, modem cards, VoIP
card, and trunk cards.

Troubleshooting the Dial Shelf Controller Card

Check the following to help isolate a problem with the dial shelf controller card:
•Are the two power LEDs on?
Verify that the power LED and MBus LED light after the dial shelf controller card has been
completely inserted into the dial shelf and the system is powered on.
—If both the MBus and power LEDs are on, the card should boot normally. During the boot
sequence, the four alarm LEDs should momentarily flash and then turn off. In addition, the
two four-character alphanumeric displays show status messages.
After the boot sequence completes, the alphanumeric display should read:
MSTR
If the boot sequence does not finish, contact a service representative for assistance.
—If either the power or MBus LED remains off, try removing and reinserting the card. If the
problem persists, contact your service representativ e. You might need to replace the card.
If the problem persists with a new card installed, remove the dial shelf controller ca rd from
the dial shelf slot and examine the backplane for bent connector pins.
To inspect the backplane pins, first power OFF the system to avoid hazards caused by high
voltages present on the backplane connectors. Next, remove cards in neighboring slots to
allow an unimpeded view of the backplane connectors. Then, using a flashlight, verify that
the backplane connectors are in good condition. If you discover bent pins, you need a new
backplane. The backplane is an FRU. Contact your service representative to order a new
backplane.
•You can also use the show command to diagnose a problem with the dial shelf controller card.
Enter the following command:
router> enable
enter password <password>
router# show diag <type {shelf | slot}>
Ctrl-Z