(347) 552-2258 [email protected]

820-3476-A Won't Charge Battery/Run Off Charger

C

CRC2018

Member
Hope someone can help with this one as it's proving to be a complete pain.
History: Macbook brought in with liquid damage and no power. Inspection revealed liquid damage around Q7130 which had also burned Q7130 and the CHGR_PHASE pad underneath. Smaller amount of liquid damage around U7100.

What I have done so far:
Run a jumper wire for CHGR_PHASE between Q7130 and L7130
Checked for any obvious shorts to ground on PP_BUS, CHGR_PHASE, CHGR_LGATE, CHGR_SGATE - found none
Replaced U7100 and Q7130 - multiple times as a pair with new chips
Replaced R7121 and R7122 and checked resistance between pins 27 and 28 of U7100 to confirm 20ohms
Replaced R7151 and R7152 and checked resistance between pins 17 and 18 - found even after replacement it wasnt 3ohms so traced the fault back and found no continuity between R7152 and R7150
Ran a jumper wire between R7152 and R7150 and checked resistance between pins 17 and 18 - now reads 3ohms
Replaced R7125 and C7125 as they didnt look nice - tested ok with the meter but replaced anyway
Found R7185 is only reading 1.2kohm instead of 470k as per spec - replaced it and C7185 but it still reads 1.2kohm makes me suspect Q7180 has an issue but I am getting PP_DCIN_CHGR at 19v with my 85w charger.

Currently the board will:
Run fine off a charged battery - which points me squarely at an issue with the charger input side of the circuit.
It will also run off a charger but I believe Q7130 to be partially burned now as it is allowing around 17V through it to make PPBUS 17v which obviously means the system won't charge the battery as the voltage is to high.

Just for reference with a previous Q7130 and U7100 I was only getting 4V on PPBUS
 
J

JohnB8812

New member
Replace the ISL, Q7130, and Q7155 all at the same time. Also double check all traces under and around Q7130
 
J

jadao

Member
You can also check scl/sda lines diode mode, they should be really close one each other, usually around 0,489-0,500.
Check resistor values R5380, R5381.
Check for any short on both lines.
Make sure U7100 is well soldered.
 
2informaticos

2informaticos

Administrator
Staff member
"R7185 is only reading 1.2kohm instead of 470k"
Change Q7180, as bad; it has leakage at least.

"Run a jumper wire for CHGR_PHASE between Q7130 and L7130"
Have U7100 and C7125 good connection to the same point?
Open trace for R/C7125 will burn Q7130 (its high-side).
 
C

CRC2018

Member
Thanks for your replies - can confirm after having replaced Q7180, U7100 and Q7130 again and also running a jumper wire for CHGR_PHASE from L7130 to C7125 the macbook is now charging and producing 12.3v PPBUS from the charger as normal.

thanks for your advice.
 
2informaticos

2informaticos

Administrator
Staff member
"producing 12.3v PPBUS from the charger as normal."
That is not normal!
Unless your multimeter doesn't read correct.

Battery is charging?
 
C

CRC2018

Member
my meter does read a little low normally - yes the battery is charging as normal. Keep meaning to invest in a better meter!
 
You must log in or register to reply here.
Top