820-3435 SMC resettin constantly.

[BCN_Techs]

Hi,

Have 820-3435 logic board with water damage in U7090 area. First there was no green light and ppbus. Fixed it replacing U7090 and R7006.

Now when plug magsafe it going orange -> green - > orange -> just like something is reseting smc constantly. Checked SMC _RESET_L and it has 3.4 V droping to 3V when charger light goes green.

There was corrosion near J6100 and i removed it completely.

Any suggestion?

 

[2informaticos]

3V42 fluctuates too?

 

[BCN_Techs]

No, it's stable.

 

[2informaticos]

Remove R7100 and check if SMC_RESET_L still fluctuates.
Use o-scope, if possible; it can show if voltage drop to 0V.

Post all voltages of U5110.
Take time and check which ones fluctuates.

 

[BCN_Techs]

Removed R7100 and SMC_RESET_L is stable. Magsafe orange.
U5110
1 3.4V
2 0V
3 3.4V
4 2.8V
53,4V (about 0,1V fluctuation)
63,4V (about 0,02V fluctuation)
7 3,4V (about 0,02V fluctuation)
8 3,3 V
Right now dont have o-scope. Can try to check it tomorrow.

 

[2informaticos]

"Removed R7100 and SMC_RESET_L is stable."
Then change U7100.

 

[BCN_Techs]

Already changed but will try again. Muchas gracias informaticos