FCO A0291-1: Sun Fire V440 Power Supply may fail prematurely due to fan degradation issue.

Asset ID:	1-73-1019231.1
Update Date:	2010-09-15
Keywords:

Solution Type FAB (standard) Sure

Solution 1019231.1 : FCO A0291-1: Sun Fire V440 Power Supply may fail prematurely due to fan degradation issue.

Impact

Power Supply Unit (PSU) on Sun Fire V440 (Non-RoHS) systems may fail prematurely due to PSU fan degradation. In some cases, this may lead to an orderly thermal shutdown of the system.

Contributing Factors

Power Supply (Sun p/n 300-1501) shipped on Sun Fire V440 (Non-RoHS) before December 01, 2005 may fail prematurely as it uses the Minebea (NMB) fan that may be susceptible to premature degradation based on environmental conditions.

Symptoms

The affected V440 PSU (Sun p/n 300-1501) initially works in a degraded state with increased fan noise, increased fan vibration levels, and/or decreased fan RPMs, eventually leading to fan failure.

If PSU fan speed goes below 2,520 RPM (slow fan), a predictive fan fault signal is triggered by the system similar to the below example;

"PS0 fan is operating below its normal threshold"

However, if the PSU fan actually fails and the PSU turns off, the system outputs the message;

"PSU @ PS0 has FAILED"

...and, depending on the environment, the system may initiate an orderly shut down to avoid overheating. Primary impact to the customer in such a scenario would be unplanned downtime.

Root Cause

Sun Fire V440 PSU (Sun part number 300-1501) used a Minebea (NMB) fan with open-bearing motor design which is susceptible to dust accumulation and loss of lubrication over time under certain environmental conditions. The resulting degradation of the open-bearing fan motor due to increased friction leads to increased fan noise, increased fan vibration levels, and decreased fan RPMs with eventual fan failure.

Sun started using a closed bearing fan during production of the 300-1501-10 PSU acquired from a different vendor (Nidec) in November of 2005 (date code WW 45 and later). The follow-on substitute part for this PSU is the RoHS V440 PSU part number 300-1851-01, which also uses this closed bearing Nidec fan. PSUs with closed bearing fan design eliminates this degradation mode.

Corrective Action

Workaround

No workaround available - see Resolution section below.

Resolution

Upon Failure Only replace 300-1501-10 (or below) having a Minebea (NMB) fan with a 300-1501-10 or a 300-1851-01 (or above). RSL stock consists of 300-1501-10 (with Nidec fan) and 300-1851 PSUs.

Only the failed PSU should be replaced - the second working PSU should not be proactively replaced. Our analysis shows that one PSU failing in the system does not necessarily lead to the second PSU failing in the same system soon thereafter. Therefore, this lends little support to proactive replacements beyond the failed PSU.

Failed 300-1501 PSUs have been getting updated at the Repair Vendor by replacing the Minebea fan with a new Nidec fan.

Hardware Remediation and Material Availability Details:

All Regions/Timezones were materially ready at the time this FAB was published. Check with your Logistics Representative or TZ / Country / Area FCO Manager for more information with regard to material availability and the parts ordering process for this FCO.

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
SSG WGS (Workgroup Systems)

Internal Sun Alert & FAB Admin Info
30-Apr-2008: Put completed FCO Communication draft into IBIS and out to FCO Tiger Team for review . Awaiting Material Readiness update.
02-May-2008: Material Readiness confirmed in all Regions. Sending to Publish.
16-May-2008: Removed "How to Identify" section as it proved confusing.
05-Mar-2009: Highlighted "Upon Failure Only" and removed Proactive option from Resolution.
17-Dec-2009: Replaced Product with Swordfish Nomenclature

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