Cisco 10000 Series Router Troubleshooting Guide
PEM Faults and Blower Failures
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PEM Faults and Blower Failures

Table Of Contents

PEM Faults and Blower Failures

DC PEM Faults

AC PEM Faults

Other Electrical Problems

Blower Module Faults


PEM Faults and Blower Failures


The following sections provide methods for troubleshooting faults involving the Cisco 10000 series router Power Entry Modules (PEMs) and blower modules.

This chapter contains the following major sections:

DC PEM Faults

AC PEM Faults

Other Electrical Problems

Blower Module Faults

DC PEM Faults

DC PEMs can be installed in two modes—redundant and nonredundant. It is recommended that you install PEMs in a redundant configuration. A PEM failure in a nonredundant configuration causes a system failure.


Tip To quickly check the functional status of your PEMs, use the show environment command.


DC PEM faults can occur for the following reasons:

PEM failure

Reversed power cables

Backplane interface failures or damage

Figure 2-1 illustrates the DC PEM and its indicators. Table 2-1 describes the indicators.

Figure 2-1 DC PEM

Table 2-1 DC PEM LEDs

LED
Description

Power (green)

PEM is powered on and is operational.

Fault (yellow)

PEM is not operating correctly or the circuit breaker is in the off position.

Miswire (yellow)

Input power cables are wired incorrectly and should be reversed.


Table 2-2 lists the DC PEM fault symptoms and corrective actions.

Table 2-2 DC PEM Fault Symptoms and Corrective Action 

Fault Symptom
Corrective Action

Green LED on PEM fails to light

1. Make sure the circuit breaker on the PEM is turned on.

2. Make sure the PEM is properly seated and screwed in place.

3. Make sure power leads are properly connected to power connectors on the backplane. If connections are loose or their polarity is reversed, chassis does not receive power.

4. Check the external power source.

5. Move the PEM to the other PEM slot. If the PEM still fails, replace it.

PEM experiences problems in one slot but operates normally in a different slot

1. Ensure that the input power to both slots is correct.

2. If the problem persists, contact the Cisco TAC.

Fault LED is lit yellow

1. Check to see if the circuit breaker (on/off switch) has tripped. If it has, return the switch to the on position.

2. Replace PEM with a known good replacement.

3. Contact the Cisco TAC.

Miswire LED is lit yellow

If the MISWIRE LED is on, the power cables are reversed. Power off the PEM and the external power source and reconnect the wires correctly. See the Cisco 10000 Series Router Hardware Installation Guide.



Tip Securely tighten the captive screws on your PEMs to prevent heightened levels of electromagnetic interference.


AC PEM Faults

AC PEMs can be installed in two modes—redundant and nonredundant. It is recommended that you install PEMs in a redundant configuration. A single PEM failure in a nonredundant configuration causes a system failure.


Tip To quickly check the status of your PEMs, use the show environment command.


AC PEM faults can occur for the following reasons:

PEM failure

Backplane interface failures or damage

Figure 2-2 shows the AC PEM and its LED indicators.

Figure 2-2 AC PEM

Table 2-3 describes the AC PEM LEDs located at the bottom of the front panel.

Table 2-3 AC PEM LEDs

LED
Status
Condition

POWER

Steady green

Power is available.

FAULT

Steady yellow

PEM has failed or is turned off.


Table 2-4 lists the AC PEM fault indications and recommended actions.

Table 2-4 AC PEM Fault Indications and Recommended Actions

Symptom
Steps to Take

Power LED on PEM fails to light

1. Make sure the power switch is in the on position.

2. Make sure the PEM is properly seated and screwed into place.

3. Make sure the power cable is plugged in properly.

4. Check the power source.

5. Move the PEM to the other PEM slot. If the PEM still fails, replace it.

6. If the problem persists, contact the Cisco TAC.

Fault LED is lit yellow

1. Make sure that the PEM is switched on.

2. Replace the PEM.

3. Call the Cisco TAC.


Other Electrical Problems

If the electrical problem cannot be traced to a PEM, check the unit for:

Improper power cable connections to the Cisco 10000 series router

Improper installation of other field-replaceable units (FRUs)

Check the site for:

Improperly grounded equipment, particularly equipment racks and power grounds

Fluctuating voltage, which can result from excessive power drains caused by other equipment (such as air conditioning units)

Cable corrosion or defective power panels, circuit breakers or fuses, or cable connections

Undersized power cables or excessive power cable lengths

Excessive power demand on backup power systems or batteries when alternate power sources are used

Blower Module Faults

The blower module is critical to the operation of the Cisco 10000 series router. Severe overheating can result in system failure. The blower module contains a redundant array of fans in a single shelf unit.

Figure 2-3 shows the blower module front panel and its LED indicators.

Figure 2-3 Blower Module

Table 2-5 lists the blower module fault indications and recommended actions.

Table 2-5 Blower Module Fault Indications and Recommended Action

Symptom
Steps to Take

Fans OK LED on blower module fails to power on

1. Make sure the blower module is fully inserted into the chassis.

2. If you use DC PEMs, make sure the wiring is not reversed.

3. Replace the blower module.

FAN FAILURE LED is lit

Replace the blower module.

MULTI-FAN FAILURE LED is lit

Replace the blower module.

Fans run but the system overheats

1. Make sure that all intake and exhaust vents on the front and rear of the chassis are free of blockages.

2. Make sure that the ambient temperature and other environmental factors in the system area are within the ranges specified in the "Using the show environment Command for Basic Troubleshooting" section.

3. Make sure all line cards and blank faceplates are in place. The cooling system cannot operate effectively unless the chassis is fully enclosed.

4. Check the air filter, and if necessary clean or replace it.

5. Reduce the ambient temperature of the area surrounding the router chassis.