[Trac #696] Power supply failure in a system.

[Zarro Boogs per Child]

#696: Power supply failure in a system.
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 Reporter:  jg        |       Owner:  mfoster
     Type:  defect    |      Status:  new    
 Priority:  high      |   Milestone:  BTest-2
Component:  hardware  |    Keywords:         
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 A capacitor failed in one unit's power supply (Bert Freudenberg's machine,
 IIRC), causing a melted spot on the cover of one machine and a bad smell;
 the capacitor had melted the plastic and completely failed.

 The unit was sent back to Quanta for failure analysis.  This is a summary
 of the extensive analysis performed.

 Extensive failure analysis has been performed.   From looking at the
 design, the worst case appears to be inserting and removing a battery from
 the machine while the power supply is plugged into the unix. 300 cycles of
 battery removal and insertion on 20 different machines were executed to
 see if the failure could be induced. We were unable to induce another
 failure, despite these extensive tests, induce another failure like this
 and no other BTest-1 system has since had a similar failure.

 In the process of the failure analysis, the capacitor in the power supply
 design was found to be specified incorrectly, and its margins increased in
 the BTest-2 build.

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Ticket URL: <http://dev.laptop.org/ticket/696>
One Laptop Per Child <http://laptop.org/>