820-3437B Not charging

[Bouba148]

Hi Team,
I've this board that is not charging , no sign of WD, and already swapped battery

With the battery connected and the board ON :
ppbus: 8.37V
activity on SCL and SDA lines
pin 4 of Q7155 is mesuring 0.969V then pulsing to 8.35V in cycle.....which doesn't allow the battery to charge.
Also when the mba is OFF the board is not pulling power: 0.008A and at Pin4 of Q7155 it clycling between 0V to 7V in loop and clycles also at pin 5 from 0V to 5V
Already replaced Q7155 and U5601: without succes
I'm suspecting U7000 or upstream, have to find the reason of that interruption on pin 4 of Q7155......

 

[2informaticos]

OSX reports battery percentage?
Does it start on battery alone?
Use another battery, with some charge, for this test; if original is drained.

Post CHGR_A/BMON with board on/off and battery present and not.

 

[Bouba148]

Yes OSX reports percentage
Yes it's starting with the battery alone
I'm using a battery charged at 70%

Board OFF with Battery Only:
CHGR_AMON: 0.00V
CHGR_BMON: 0.049V

Board ON with Battery Only:
CHGR_AMON: 0.00V
CHGR_BMON: 0.100V

Board OFF with Battery and Charger:
CHGR_AMON: 0.660V
CHGR_BMON: 0.00V

Board ON with Battery and Charger:
CHGR_AMON: 0.880V
CHGR_BMON: 0.49V

 

[2informaticos]

"CHGR_BMON: 0.49V"
Looks like battery is charging.
At least this signal shows battery receives current from MLB.
Unless you have a problem with R7150-52, or traces to pins 17/18 of U7100.

 

[Bouba148]

I checked the resistance R17/18 and it's ok: around 3 Ohms.
I've seen like a short between pin 15 and 16 of U7100 and reflowed as shown in the attached pictures, I've also resoldered J6950, but it didn't solved the issue.



I've noticed that with the battery completly empty I'm reading 8.55V for PPVBAT_G3H_CONN, usually when the battery is not full it should mesure under ppbus (8.55V) , like between 7V to 8.55V no?
It's acting like the battery is full no?

 

[Bouba148]

Hi,
Just to let you know that the problem is fixed.
Now with the board ON it's pulling almost 3 Amps, CHGR_BGATE stays low and pulsing like before.
I can see the percentage rising quite fast.
I fact, I think that in all the things I did, one of them solved the issue except that the battery was continiouly showing 1%. This one is dead.
So I replaced it with another one now it's charging normally.

Again thanks for your support and patience

You can set this Topic as Solved. but i you could just answser to the question regarding the battery logos......thanks

Best Regards

 

[2informaticos]

Left side logo shows battery is charging.
Right side not charging, probably "Replace now" advice in drop down list menu for battery...

 

[Bouba148]

Thank you Vali