Sun Blade 6048/6000 midplane replacement/upgrade may damage airflow gasket causing potential electrical short.

Asset ID:	1-73-1021736.1
Update Date:	2010-08-18
Keywords:

Solution Type FAB (standard) Sure

Solution 1021736.1 : Sun Blade 6048/6000 midplane replacement/upgrade may damage airflow gasket causing potential electrical short.

Impact

When replacing or upgrading the Sun Blade 6048 or Sun Blade 6000 midplane, if care is not taken, there is potential to damage or loosen the 4-inch airflow gaskets that reside on the left and right sides of the chassis frame, parallel to the midplane. If these airflow gaskets are damaged or loosened they could make contact with the CMM foxconn connector on the midplane, which could lead to an electrical short. If this connection is made there may be a burning smell and smoke from the foxconn connector. This causes the foxconn connector on the midplane and the CMM to be damaged and ultimately to need replacement.

Contributing Factors

At publication time of this FAB, all Sun Blade 6048 and Sun Blade 6000 chassis are susceptible to this issue if care is not taken when replacing the midplane to ensure no damage is caused to the airflow gaskets.

Symptoms

Worst case there will be a burning smell and smoke along with PSU fault LEDs being lit and/or Fan LEDs being lit. PSU1 has been seen to shutdown from the overcurrent. The foxconn connector when inspected will be melted to some degree. The CMM may simply not work at all depending on how long current was running before the issue was noticed.

If this issue is discovered before the short takes place the airflow gasket will be damaged and it may be seen hanging from the chassis frame inside or may appear malformed.

Root Cause

This issue is due to there being a very small tolerance between the airflow gasket and the midplane, so there isn't much room for error when replacing the midplane. This issue is also exacerbated by the fact that the airflow gasket is made of a metallic braided material which is conductive, so if contact is made with the midplane a short to ground is created.

Please note that chassis shipped from the factory have not exhibited this failure. In all cases to-date the issue has been caused by the process of replacement/upgrade of the midplane.

Corrective Action

Workaround:

For the SunBlade 6048 chassis, during replacement/upgrade of the chassis midplane, the airflow gaskets should be removed completely.

For the SunBlade 6000 chassis, if during replacement/upgrade of the chassis midplane the airflow gasket is damaged or loosened in any way, engineering recommends removal of the gasket completely so that an electrical short hazard is not present.

Resolution:

Engineering has completed testing on the SunBlade 6048 chassis, concluding there is no thermal impact in removing the airflow gaskets altogether. This will be implemented in the factory on future released chassis under ECO WO_42452.

Currently engineering is investigating different options for the SunBlade 6000 chassis including removal of the airflow gaskets altogether.

Identification of Affected Parts (how to):

To identify damaged airflow gaskets visual inspection is required. You must remove both of the end blades to view the gasket on either side of the internal chassis frame walls. This would be blade 0 and either blade 11 or 9 depending on whether referring to a Sun Blade 6048 or a Sun Blade 6000 respectively. The gasket runs along the upper edge of the chassis wall parallel to the midplanes on both left and right side edges. If replacing the midplane, all blades and chassis components must be removed anyway so the gaskets can easily be viewed for inspection.

A picture is attached (or available via the below URL) of a good right hand side airflow gasket so that engineers can see how it should look. If the gasket is damaged or loose in anyway the gasket should be removed completely from both sides.

http://sdpsweb.central/FIN_FCO/FAB/274690/SPE/Example-Gasket_Good.jpg

References:

Escalation ID: 72041784

For information about FAB documents, its release processes, implementation strategies and billing information, go to the following URL:

http://tns.central/fab

For Sun Authorized Service Providers go to:

http://tns.central/SPE/fab/

In addition to the above you may email:

[email protected]

Internal Contributor/submitter
[email protected]

Internal Eng Responsible Engineer
[email protected] Responsible Manager: [email protected]

Internal Services Knowledge Engineer
[email protected]

Internal Eng Business Unit Group
Systems Group-x64 (X4100-X4600 (and M2), V20z/V40z/V60z/V65z, Ultra20/40 (and M2) Workstations)

Internal Sun Alert & FAB Admin Info
19-Dec-2009: Completed draft and sent to Extended Review.
22-Dec-2009: No feedback from Ext Rvw - sending to Publish.

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