#2878 NORM Product: Mismatched plating types

[Zarro Boogs per Child]

#2878: Mismatched plating types
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 Reporter:  jg                     |       Owner:  vance.ke        
     Type:  defect                 |      Status:  new             
 Priority:  normal                 |   Milestone:  Production Start
Component:  manufacturing process  |     Version:  BTest-4 Hardware
 Keywords:                         |    Verified:  0               
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 http://wiki.laptop.org/images/2/25/OLPC_BR_Audit.pdf

 Several connector pairs have mismatched plating types, with gold on one
 side and tin on the other. And pairs are inconsistent with gold on gold in
 some machines while tin on gold in others. Gold flash is possible in some
 that appear tin, but it was not observed. This may be a supply issue but
 if you are paying for gold, you  hould get gold.

 This brings up the potential of fretting corrosion on the tin on tin
 connectors (or tin on gold for that matter). The battery cable to cable
 connector mounted under the handle is a good example. Photos of this
 connector show dark deposits of tin oxide present which is a sign of
 either fretting corrosion, or simply oxidized tin resulted from the first
 insertion. Machines which have experienced vibration and/or thermal
 cycling, should be disassembled and inspected for signs of fretting
 corrosion, especially on the battery cable connector. The floating nature
 of this design should prevent relative motion, and is good practice.
 Still, a resistance check and visual inspection of connectors from thermal
 and vibration test machines, will be important to verify the design.

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Ticket URL: <http://dev.laptop.org/ticket/2878>
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