820-00138 - not charging - magsafe green light blink [SOLVED]

[nameless]

Hey everybody

I've got an issue with 820-00138 motherboard.

It doesn't charge the new battery, had to replace as previous, was inflated.

History : a customer brought the laptop cause wasn't powering on. When opened, the battery was inflated with a lot of dusty mess all around

So I replaced the battery and cleaned all around. After a week a so the happy customer came back saying it wasn't charging( or very slow during night when not used)

So now when plugin different (original) know working magsafe chargers it blinks green. When unplug the battery the magsafe stays steady amber.

The macbook works but unable to charge.

Here some measurements i did (based on similar issue from forum) :

PPBUS_G3H on F7700 - 16.21V - without battery connected
PPBUS_G3H on F7700 - fluctuates 10.81V to 16.1V - with battery connected
SMC_CHGR_BMON - on R5423 - 0.66mV - without battery
SMC_CHGR_BMON - on R5423 - jumping from 0.66mV to 253 mV - with battery
Resistance between pins 27/28 on U7100 - 21.4 omhs
U7001 - pin 5 - 3.42V
U7001 - pin 1,2 - fluctuates from 0 up to 4V when battery and charger connected
U7100 - pin 14 - fluctuates from 0 up to 4V when battery and charger connected
U5000 - R5187 - 2.8V

U7100 was corroded (here some pics) replaced with donor board magsafe still blinking

All measurements were made with original U7100 cleaned and resoldered

Thank you for your help

Regards

 

[nameless]

btw forgot to mention, tested with two original magsafe
and two different batteries known good

 

[2informaticos]

"PPBUS_G3H on F7700 - 16.21V - without battery connected"
Are you sure???
If yes, change Q7130.
Be sure C7125 is good.

 

[nameless]

oh sorry 20V with 85W charger and 16.21V with 60W charger
checked Q7130 getting 20V with 85W charger
C7125 wasn't sure if good so replaced from donor
Went from 1.3 mohms to 0.5 mohms

 

[nameless]

btw i'm getting fluctuating voltage on pin 1 on U7100 (w/wo chip) from 0 up to 9V (15V on donor board)

 

[2informaticos]

Change Q7130, is shorted D-S!!!

 

[nameless]

oh that would be great

can you please explain how u know ? )

 

[2informaticos]

If you get the same input/output voltage, what do you expect?

 

[nameless]

thanks for your reply

I removed the Q7130 and it was shorted indeed ))

I ordered a new part https://www.mouser.fr/ProductDetail/863-NVTFS4C06NWFTAG

Which I received but its too small ))

Here some pics

Do you know where can I get this part ? cause the donor board doesn't have the same and I can't find the same specs

Thank you

Best regards

 

[2informaticos]

You can get it from normal laptop boards too (not Apple only).
The high-side MOSFET from any CPU/GPU power supply is more than you need; just pick the correct package.

 

[nameless]

lol thanks for your support ))

took it from HP mb and booom

where can i mark as SOLVED !!

 

[2informaticos]

Glad to hear is solved.
Not really need to mark as solved; probably editing the title...