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Hardware Troubleshooting

Hardware Troubleshooting

This appendix contains procedures that help you troubleshoot physical problems with a Catalyst 3920 Token Ring Switch and its connections to other devices.

This appendix contains the following information:

Obtaining Service

Caution There are no operator-serviceable parts in the Catalyst 3920. Do not remove the cover for any reason. Refer servicing to qualified personnel.

Summary of the Hardware Troubleshooting Process

If one or more devices (such as a computer) connected to a Catalyst 3920 are unable to communicate with other devices in the network, use the following steps to start the troubleshooting process:

Step 1 Using the network sketch, the label on the cable connected to the device, or other network records, locate the Catalyst 3920 to which the device is connected.

Step 2 If you have set up a console session (described in the "Planning for Configuration and Management" chapter), it can be used to determine whether diagnostics have been completed correctly. Refer to the "Resetting the Catalyst 3920" chapter for more information.

Step 3 Observe the LEDs on the Catalyst 3920 front panel. Review the "Understanding the LEDs" section before proceeding with the troubleshooting process.

Step 4 Select a troubleshooting procedure as described in the "Choosing a Troubleshooting Procedure" section.

Understanding the LEDs

The Catalyst 3920 has three sets of LEDs on the front of the switch; those for the switch, those for the stack, and those for the individual ports. It has one set of LEDs on the back of the switch for the power source.

Switch LEDs

Table C-1 lists the Catalyst 3920 status LEDs and their meanings.


Table C-1: Catalyst 3920 Status LEDs and Their Meanings
LED Position State Meaning

PWR

Top left

On

Power supply current is good.

Off

Power supply current is bad.

Mode

Middle left

On

Boot is in progress.

Off

Catalyst 3920 is working correctly.

Blinking

The FLASH update portion of a TFTP download is in progress.

FLT (fault)

Bottom left

On

Power-on failure has occurred.

Off

Catalyst 3920 is working correctly.

Stack LEDs

Table C-2 lists the stack LEDs and their meanings.


Table C-2: Stack LEDs and Their Meanings
LED Position State Meaning

TX (transmit)

Top right

On

Stack port is transmitting.

Off

Stack port is not transmitting.

RX (receive)

Middle right

On

Stack port is receiving.

Off

Stack port is not receiving.

AT (attach)

Bottom right

On

Stack port is attached to the stack.

Off

Stack port is not attached to the stack.

Port LEDs

Table C-3 lists the port LEDs and their meanings.


Table C-3: RJ45 Port LEDs and Their Meanings
LED Position State Meaning

INS (insert)

Left

On

Port is inserted.

Off

Port is not inserted.

ACT (activity)

Right

On

Port is transmitting or receiving.

Off

Port is idle.

Power Supply LEDs

Table C-4 lists the power supply LEDs and their meanings.


Table C-4: Power Supply LEDs
LED Position State Meaning

RPS PRESENT

Top

On

RPS is connected to the Catalyst 3920 and to an AC power source.

Off

RPS is not connected to the Catalyst 3920 or it is not connected to an AC power source.

RPS GOOD

Middle

On

RPS is supplying power to the Catalyst 3920.

Off

RPS is not supplying power to the Catalyst 3920.

INT PS GOOD

Bottom

On

Internal power supply is providing power to the Catalyst 3920.

Off

Internal power supply is not providing power to the Catalyst 3920.

Table C-5 describes the meanings of the combinations of LEDs.


Table C-5: Understanding the Power Source LEDs
RPS PRESENT RPS GOOD INT PS GOOD Meaning

Off

Off

On

No RPS is installed. All power is being provided by the internal source.

On

Off

On

The RPS is installed, but not functioning. All power is being provided by the internal power source.

On

On

On

The RPS is installed. The switch is configured in a quasi-redundant configuration. The internal power source is providing the power and the RPS is ready to provide power if needed.

On

On

Off

The RPS is installed. One of the following is true:

The switch is configured in a quasi-redundant configuration. The internal power source has failed and the RPS is providing power.

The switch is configured in a fully-redundant configuration. The internal power source is not connected to an AC source. The RPS is providing both primary and back-up power. It is not possible, however, to determine whether the primary RPS connection is providing power or the primary has failed and the RPS has switched over to back-up power.

Choosing a Troubleshooting Procedure

Use Table C-6 to determine which troubleshooting procedure you should use.


Table C-6: Symptom, LED State, and Recommended Troubleshooting Procedure
Symptom and LED State Procedure

All LEDs are off.

A

FLT LED is on.

B

None of the devices connected to the Catalyst 3920 can communicate, the FLT LED is off, and the Power LED is on.

C

Single device connected to the Catalyst 3920 is having trouble communicating.

D

Procedure A

Use the following procedure if all LEDs are off:

Step 1 Verify that the power cord is connected at both ends and that the power outlet is working.

Step 2 If the power cord is connected correctly, the outlet is working, and the problem persists, the problem is in the Catalyst 3920. Contact the Cisco TAC.

Procedure B

Use the following procedure if the FLT LED (amber) is on:

Step 1 Reset the Catalyst 3920 by disconnecting the power cord. Wait 10 seconds and then reconnect the cord. If the problem goes away, resume using the Catalyst 3920.

Step 2 If you have just downloaded new software, clear NVRAM and reset the Catalyst 3920 using the instructions in the "Resetting the Catalyst 3920" chapter.


Note Clearing NVRAM returns all configuration parameters to their default values.

Step 3 Reset the Catalyst 3920 and monitor the diagnostic messages for individual port failures. Correct any individual port problems that are detected.

Step 4 If the problem persists, the problem is in the Catalyst 3920. Contact the Cisco TAC.

Procedure C

Use the following procedure if all devices connected to the Catalyst 3920 have communication problems, the Catalyst 3920 FLT LED is off, and the Mode LED is off:

Reset the Catalyst 3920 by disconnecting power cord for 10 seconds. Reconnect the power cord.

Procedure D

Use the following procedure if one device connected to the Catalyst 3920 is having a communication problem, the Catalyst 3920 FLT LED is off, Mode LED is off, and other attached devices can communicate through the Catalyst 3920:

Step 1 Check the port LEDs.

Step 2 If the Connect LED on the failing port is on and the attached device still cannot communicate, do the following:

Step 3 Determine whether the port has been disabled:

Step 4 Restart the communications program on the failed connected device.

Step 5 If the Catalyst 3920 is connected to a Token Ring concentrator, perform the following steps:

Step 6 For each device that is having a communication problem, connect its segment to another Token Ring port on the Catalyst 3920. Try each of the remaining ports to determine whether the problem is in a particular port.

Step 7 The problem does not appear to be in the Catalyst 3920, the cables, or the devices connected to the Catalyst 3920. The problem might be in the network applications or other software running on the devices that are having the communication problem. Refer to the software documentation for software problem determination procedures, or consult your network administrator.


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Posted: Tue Oct 12 13:50:04 PDT 1999
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