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Cisco MGX 8880 Media Gateways

Field Notice: FN - 62633 - MGX PS-1200-AC - Undetected Fan Failure in Redundant Slot Power Supply Will Cause Crash on Failover - RMA on Failure


Revised March 5, 2008
September 26, 2007


NOTICE:

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE FIELD NOTICE OR MATERIALS LINKED FROM THE FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.

Revision History

Revision Date Comment
1.1 05-MAR-2008 Removed Upgrade form and updated Title and Workaround/Solution sections to reflect the change.
1.0 26-SEP-2007 Initial Public Release

Products Affected

Products Affected Top Assembly Comments
Part Number Revision
PS-1200-AC
800-04746-02
C0
Power supply PID, also used in multiple bundle PIDs - see table in Background section. All use same TAN.

Problem Description

The 1200 Watt Power Supply for AC Systems on the MGX platforms may exhibit an undetected fan failure when installed in a redundant power supply slot in the chassis. This is due to a defect with one of the two supply vendors for this part.

This malfunctioning redundant power supply will lead to unexpected system failure if the redundant supply is switched to due to primary power supply failure. A fully loaded system may not have sufficient power available at switchover due to an unreported failure of one or more of the redundant supplies.

Background

Two suppliers have been used while shipping TAN 800-04746-02, Vendor 1 and Vendor 2. This failure exists only with the Vendor 1 power supply.

The Vendor 1 supply was shipped from 2000 to 2005 and is no longer used in the MGX product.

The primary Product ID is PS-1200-AC. All of the following PIDs use the same base part:

Problem Symptoms

A redundant power supply unit has malfunctioned due to a fan failure that was not detected or reported by the system. No visual symptoms are shown.

If the system subsequently switches to redundant power supply due to a primary power supply failure, it may crash without warning if the redundant side has insufficient power available due to a unit failure.

Workaround/Solution

Workaround:
Do not use the Vendor 1 supply in a redundant slot on the chassis because a fan failure will not be detected. Use in a primary slot will generate a failover message if the Vendor 1 power supply fails.

Solution:
Upgrade the power supply with one that has a TAN of 800-04746-03 or higher. Contact TAC to place an RMA request.

How To Identify Hardware Levels

Methods to differentiate between Vendor 1 (affected) and Vendor 2 (unaffected) power supplies include:

1) If the power supply is located outside the chassis, use the manufacturer's label.

2) If the power supply is located inside the chassis check the following.

Fan - Vendor 1 (affected) units have a metal grill fan guard whereas the Vendor 2 (unaffected) units do not.

LED - Vendor 1 units have a protective black plastic protruding from the surface around the LED's labeled DC and AC whereas the Vendor 2 units do not.

3) The Vendor 1 power supply can be identified by a serial number that begins with "ABD".

Serial numbers may be obtained by looking at the manufacturer's label (see images above). Note that Vendor 2 does not show the serial number on the label. Alternatively, electronically check the serial number through SNMP using a Network Management System:

i) Customer starts their NMS (Network Mgmt Systems)

ii) Run SNMP Walk for OID (Object identifier) --- 1.3.6.1.2.1.47.1.1.1
(entPhysicalTable).

iii) Look for Hardware devices - in this case power supplies (unit #1, 2, 3 .....).

iv) When power supplies have been identified note their corresponding index
location (ex. 17236105)

v) Check entPhysicalSerialNum with the noted index. Corresponding
entries would be the PS serial numbers

vi) See sample outputs (S/N)
entPhysicalSerialNum.17236105 = ABDXXXXXXXX (Vendor 1)?------------ Affected Supply

entPhysicalSerialNum.17236106 = BNXXXXXXXXX (Vendor 2) ?------------Unaffected Supply

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:

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