Cisco Systems OL-11497-03 manual Problem Solving with Subsystems

Chapter 4 Troubleshooting the Installation

Problem Solving with Subsystems

Step 14 Exit global configuration mode by entering Ctrl-Z.

router(config)# Ctrl-Zrouter#

Step 15 Reboot the router and use the recovered password with the enable command to gain access to the router.

Problem Solving with Subsystems

The key to solving problems in the system is to try to isolate the problem to a specific subsystem. The first step in solving startup problems is to compare what the system is doing to what it should be doing. Because a startup problem is usually attributable to a single component, it is more efficient to first isolate the problem to a subsystem rather than troubleshoot each component in the system.

For troubleshooting purposes, Cisco 12006 and Cisco 12406 Routers consist of the following subsystems:

•Power subsystem—Includes the following components:

–AC-input or DC-input power distribution unit (PDU)

–AC-input power supplies or DC-input power entry modules (PEMs). Cisco 12006 and Cisco 12406 Routers can be configured for source AC or source DC power. (You can not mix and match AC and DC power.)

–Chassis backplane power distribution. The –48 VDC power from the power supplies is transferred to the chassis backplane, which distributes –48 VDC power to the cards in the card cages through the backplane connectors. The blower module receives power from the chassis backplane and passes MBus data back to the chassis backplane through a PDU connector.

DC-to-DC converters on the two alarm cards convert –48 VDC to

+5 VDC and put it back on the chassis backplane, where it is picked up to power the MBus modules on other cards and the blower module.

–DC-to-DC converters. Each card in the router is equipped with DC-to-DC converters. These converters are controlled by the MBus module on each card. The DC-to-DC converters take –48 VDC and convert it into the voltages required by the card circuitry.

	Cisco 12006 and Cisco 12406 Router Installation and Configuration Guide
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