This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS74701: Debugging issues.

Part Number: TPS74701

Hello, 

My client is currently having issues with the part number specified above.

Re:

Two constant test failure on current 2071 assembly. 39 failures of each so far out of 270 boards tested out of lot a of 475 boards.  Would like to send 10 of each to "x" for evaluation.

Reset/power up test -  Power rails all or partial notcoming up.

SN 2071-010702,010622,010667,01074,010730,10715,010761,010767,010756,010739

 

PDDX3Mem Test -  Test hangs/reboots then hangs at login prompt during PDDX3Mem Test.

SN 2071-01737,010723,01734,01721,010685,01728,01713,010725,010722,010719

&

I have determined that bad LDOs are the cause of both issues. There are multiple date codes on these parts (per blade and across blades).

 

I was able to replace U37 on a blade that failed PDDX3Mem Test and it passes test now (2071-010723). Also, I replaced U35 and U27 on one of the blades failing to fully power up and it successfully passes test now (2071-010739). The other boards are available for pickup for rework and re-test.

 The part markings had the same first 2 lines and only differed on the last line. This line is provided below for reference to see if there is a trend of failures with certain date codes.

Good: D2J1, D3CK, DCFV, ASD8, APK1, D4NS

Bad: D1C4, D2JF, C05N

Any assistance would be greatly appreciated.