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Cisco uBR7100 Series Universal Broadband Routers

Field Notice: FN - 61986 - uBR7100 Series may Exhibit SNR Issues Over Time - Hardware Upgrade may be Needed


Revised September 28, 2006

September 30, 2005


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.

Products Affected

Products Affected Top Assembly Printed Circuit Assenbly Comments
Part Number Revision Part Number Revision
UBR7111
800-09298-02 and -01
All
800-08454-04, -03, -02, -01
All
See the Other Considerations section for further details.
UBR7111E
800-16745-02 and -01
All
800-08457-02, -01
All
See the Other Considerations section for further details.
UBR7114
800-09297-02 and -01
All
800-08447-04, -03, -02, -01
All
See the Other Considerations section for further details.
UBR7114E
800-16746-02 and -01
All
800-08459-02, -01
All
See the Other Considerations section for further details.

Problem Description

Bulk capacitors were installed incorrectly on some uBR71xx product. The capacitors deteriorate over time. At some point various symptoms may occur, including poor signal to noise that can cause modems to go off-line or not register.

Background

Six bulk capacitors were installed with reverse polarity on the affected uBR71xx product. Over time, these capacitors lose their effectiveness. This causes ripple on the power supply, resulting in oscillation. In turn, the SNR may degrade on the product. Units built after the ECO was instituted in June 2004 will not be affected by this issue.

Problem Symptoms

The affected product may cause modems to go off-line or prevent them from registering.

Due to the power supply oscillation, an audible buzz may be exhibited by some affected units.

Possible issues with upstream QAM operation where QPSK is still operating.

Workaround/Solution

Workaround:
There is no workaround.

Solution:
As of approximately June 2004, new products that were manufactured under Engineering Change Order (ECO) are guaranteed to be free of this problem. Refer to Other Considerations and How to Identify Hardware Levels below for instructions on how to view the version of in-service product that may be affected.

Other Considerations

To further aid in product identification, the following information details product that is considered good and not affected by the problem. The steps to confirm that the product is not affected by the issue follows. It should be compared with the show diag information obtained in the How to Identify Hardware Levels section of this notice:

First Step: Compare the Top Assembly Number (TAN) of your product to this list:
TAN = 7111: 800-09298-03 H0
TAN = 7114: 800-09297-03 H0
TAN = 7111E: 800-16745-03 G0
TAN = 7114E: 800-16746-03 G0

If your product matches or has a higher TAN than the listed value, your product is not affected by the issue and you do not need an RMA.

Next Step: If the TANs do not match up or are at a lower version and/or revision than listed above, proceed to check the serial number information from the show diag command.

An example of the serial number information follows:

serial no. = CAT0818xxxx

If the serial number is CAT0818xxxx or higher, then the boards are considered good and your product is not affected by the issue and you do not need an RMA.

How to Identify Hardware Levels

Use the Top Assembly Number (TAN) and the serial number to determine if the uBR71xx is affected by the issue. Once the information has been gathered using the show diag command, refer to the Other Considerations section to determine if your product is affected by this issue.

The TAN and serial number can be viewed by issuing a show diag command. An example of the uBR7111E output is shown below:

Slot 1:
Integrated EURODOCSIS Modem Card (ASIC) 1 Down/1 Up with Up-converter Port adapter
Port adapter is analyzed Port adapter insertion time 00:00:43 ago
EEPROM contents at hardware discovery:
Hardware Revision : 3.0
Top Assy. Part Number : 800-08457-01
Board Revision : Product Number : UBR7111E CLEI Code : KNC0559AYQ
Unknown Field (type 0020): 80 Unknown Field (type 0402): 01 PCB Serial Number : CAB0448FXEN
RMA Test History : 00
RMA Number : 0-0-0-0
RMA History : 00

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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