820-00164 strange charging issues

rob777

New member
I’m stuck, need some advice please. This board works fine on charger with no battery installed.
With a charged battery and no charger it also boots and works fine.
When battery is installed and you plug charger in, the icon says not charging the battery briefly then shows no charger connected, light flashes constantly until battery removed. Light then shows green then orange.

Replaced u7100
q7130
q7155

Changed a whole bunch of resistors around u7100 that were marginally out of spec and probably didn’t need changing.

pins 27/28 measure 20ohms
pins 17/18 measure 2.6ohms
voltage at pin 2,19 and 20 of u7100
tried new battery
ppvbat_g3h_conn pin 5 is 16.1v no battery connected. Is 7.4v with battery
r5422 and r5431 in spec
acok is 3.4v

Any advice appreciated.
 

2informaticos

Administrator
Staff member
"ppvbat_g3h_conn pin 5 is 16.1v no battery connected. Is 7.4v with battery"
So F7140 has 16V on charger only...
Seems that high-side MOSFET from Q7130 is shorted.
When you connect battery Q7180 is blocked.
Be sure pin24/U7000 is correctly soldered and C7125 is in place.

Did you surelly soldered P-channel in place of Q7155???
Check if is not shorted now...
 

rob777

New member
Yes f7140 has 16v on charger
I just replaced C7125 anyway
On Q7130 I have continuity from pins 2/3/4/9 to pin 10. This isn’t correct is it?
 

rob777

New member
Replaced q7130 again. Don’t have the continuinty to pin 10 anymore. F7140 is only 2v tho so I have something pulling it down I suppose.
 

rob777

New member
POS is fixed. Was either C7125 or I haven’t been putting Q7130 on properly. What a nightmare. Over 4hrs spent
 
Top