#10314 HIGH Not Tri: XO-1.5 won't boot

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#10314: XO-1.5 won't boot
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           Reporter:  wad       |       Owner:  wad        
               Type:  defect    |      Status:  assigned   
           Priority:  high      |   Milestone:  Not Triaged
          Component:  hardware  |     Version:  1.5-C2     
         Resolution:            |    Keywords:  XO-1.5 boot
        Next_action:  diagnose  |    Verified:  0          
Deployment_affected:            |   Blockedby:             
           Blocking:            |  
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Comment(by Gary Chiang):

 After further analysis , I found out the SHC005007AB also have similar
 problem,
 The pin HD#21 maybe soldering crack on this board.
 This pin have internal resister (55ohm ) on both CPU and VX855.
 Please find attached file for failed (HD#21_fail.PNG) and normal
 (HD#21_Normal.PNG) waveform,
 It looks like one of the pull-up resister are some how disconnected (same
 with SHC00500908 ).
 But ,I don`t know which side (CPU or VX855) are soldering crack , this pin
 only go with inner layer.
 I will pass this board to VIA tomorrow , they can do reflow BGA or remount
 the BGA to find out the actual root cause.

 BTW
 about SHC00500908 with "HDSTB1N" pin cold soldering,
 I cut off "HDSTB1N" trace on a GOOD board, the board will fail to boot and
 the failed symptom are same with #10314,
 After measure the both side (CPU and VX855) waveform on this test case.
 I am now pretty sure the cold soldering crack was occurred on CPU side ,
 rather than VX855 side.

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Ticket URL: <http://dev.laptop.org/ticket/10314#comment:13>
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