820-3476-a [SOLVED]

[iremont]

Problem with 820-3476-a not charging, customer used china replica charger, changed u7100 and isl, now when put original charger to board takes 1-15 sec to get green light. and after green/orange pulls ppbus 12v to 3.7v and no boot

 

[2informaticos]

Post U7100 voltages when voltage drop; pins 1, 2, 3, 9, 12, 13, 14, 15, 17, 19, 20, 27.
Check resistamce between pins 17/18 and 27/28.
Test if works with lab PSU, or fake charger.

D7010 and Q7180 are the first suspects.

 

[iremont]

if i remove u7100, and try charger the green/orange light after u7100 removed

 

[iremont]

U7100 removed green/orange light present
1- 15.48, 2- 16.63, 3- 4, 9- 137mv, 12- 3.42 , 13- 3.38, 14- 3.38, 15- 9.2 dropping 8.0, 17- 320mv , 19 - 5.3 , 20- 5.5, 27- 148mv
D7010 and Q7180 are good tested/changed

 

[iremont]

it turns on with charged battery when u7100 placed but no green/orange and charging.

 

[2informaticos]

Did you post U7100 voltages without the chip soldered on the board???

 

[iremont]

CASE CLOSED, r7101 was faulty, changed and everything good.