820-00850 dead 20v amp pulsing

[2informaticos]

You can try reballing it first.

 

[yair37]

i was reballing and also replace from donor board but it still act the same(20v 0.04a pulsing)

 

[yair37]

update:
the mac sometimes work for few min then shout off.. the charging Amp still pulsing..

 

[2informaticos]

Do you have known good battery?

 

[yair37]

yes i was try with new battery, i will try u7800 again..

 

[yair37]

update:
i was get and put new U7800, the mac was turn on working for 10-15min then screen was freeze and shot off and not turn on again!
charger without battery 20V A-pulsing from 0 to 0.05A
charger with battery 20V A-pulsing from 0 to 0.7A
all ports the same

 

[2informaticos]

Did you reflow U7800?
Try new chip also.

You've said doesn't turn on, but no idea which voltages appear now on the board...

 

[yair37]

PPBUS_G3H 12.3v
PP3V3_S5 0V
PP1V8_S3 0V
PP3V3_G3H 3.3v
PP5V_S4_T_USBC 0V

 

[2informaticos]

Is the machine recognized in DFU?
If not, check if all AWAKE and SLPS2R voltages are present.

 

[yair37]

yes is enter to DFU.
all AWAKE and SLPS2R voltages pulsing

 

[2informaticos]

Did you change U7800 again?

 

[yair37]

yes

 

[yair37]

can be dead again?
i was put a new one and then it was turn on after few min it was shout off and dead again.
i was replace another new one but didn't turn on again..

 

[2informaticos]

That is really strange.
Be sure to get good solders.
Did you reflow any U7800 before changed it?

 

[yair37]

yes.. also reball

 

[2informaticos]

Did it try to start after reball?

 

[yair37]

i was reball/replace U7800 again, now is stuck on 5V and 0.2A
its recognized as DFU.

 

[2informaticos]

Can you complete DFU now?

 

[yair37]

no its not complete...
now with battery 20v 0a
without battery 5v 0.2a

 

[2informaticos]

PPBUS_G3H and all AWAKE and SLPS2R voltages stable?
Also check SSD voltages.