820-00875 not turning on

[BCN_Techs]

No water damage, no history of any strange things.


PPDCIN_G3H - 5. 2V
PPBUS - 0.2V
PP5V_S5 - 0V
PP3V3_G3H -0 V
PP3V3_S5 - 0 V


LDO on both CD3215 are ok.


WHen i heat up U3100 are it starts sometimes (not always). ALready tried to change CD3215 and stil not booting

 

[2informaticos]

"PP3V3_G3H -0 V"
Fix this first.
Do you get voltage at R7020?

 

[BCN_Techs]

Get 5V at R7020


PP3V3_G3H is generated by U7000?


Any idea what it can cause board starting when heat up u3100 area ( just sometimes)



Autoreply. It is U7000 what make board start when heat up. Will reball it now

 

[2informaticos]

U7000 sends out enable for 3V3_G3H.
So post few basic voltages for U7000; P_IN, AUX_DET, MPM_PBUS, VDDA/P, EN_VR1, SMC_RST*, AUX_OK.

 

[BCN_Techs]

Reballed but something very strange happening. Heating u7000 for couple second to 100 degrees make board starts. When it is completly cold it doesnt start. U7000 is dead or about to die?


I am out now will post voltages tomorrow, but what i think about that?

 

[2informaticos]

There maybe other chip which reacts to heat.
Heat reaction appeared after reballed U7000?
Didn't try that before?

Post mentioned voltages when the board doesn't want to start...

 

[BCN_Techs]

it was U7000. Reballed again and working fine. Thank you