820-02020-A not charge

[Paky46]

Hi, I have this board that does not charge, when connecting the charger it absorbs 5V
the customer says that it has stopped charging and now the battery is completely dead. Fortunately I do not find any shorts. Where can I start?

 

[2informaticos]

Machine works, just not charge the battery?

 

[Paky46]

the customer says yes, unfortunately since I don't have another battery I can't verify it

 

[2informaticos]

You only mentioned battery not charging here.
So now you say machine not working with charger alone?
Why then you fix on not charging battery?
Please, describe correctly the problems on your posts.

Post PPBUS_AON and 3V8_AON voltages with charger alone.

 

[Paky46]

the customer told me that it doesn't charge but if I connect the charger I have no sign of charging at all, it only absorbs 5v
PPBUS_AON=0.7
PP3V8_AON=0.8
the voltage of PP3V8_AON when I measure it tends to drop

 

[2informaticos]

Post now diode mode to ground of them.

 

[Paky46]

PPBUS_AON=OL
PP3V8_AON=OL

 

[2informaticos]

I don't believe that.
Did you check with red probe connected on ground?

 

[Paky46]

sorry
PPBUS_AON=0.515
PP3V8_AON=0.177

 

[2informaticos]

0.177 looks low for 3V8_AON; compare with good board.

Remove F5200 and check C5250 voltage.

 

[Paky46]

C5250=V8.78
Unfortunately I don't have a card to compare

 

[2informaticos]

Do you mean 8.78V without fuse?
Battery also disconnected?

 

[Paky46]

Do you mean 8.78V without fuse? yes
Battery also disconnected? yes

 

[2informaticos]

No good then; should be 12.3V there (fuse removed).

Try changing U5200.

 

[Paky46]

changing u5200 now turns on and charges
Thank you