820-2879-b not charging.

Yoel Ren

Member
hi, this board came in, with problem not charging, board run off battery and detect the battery.

ppbus is 12.2v.
isl is a bit botched, so i replace it.
i replaced smc, still the same.
i tried the previous smc to another working board. i have 12.6v ppbus.

i diode mode pad under smc and found out that smbus_smc_bsa_scl is open.
so i wire it to r5281, but ppbus is still 12.2v.
smc_reset_l is present at 3.3v, but should i make sure its reaching the pad under smc ?
 

2informaticos

Administrator
Staff member
Did you check SCL/SDA voltage and diode mode?
Remove D6950 and test again.
Also disconnect BIL (J6955).
 

Yoel Ren

Member
both diode mode is the same at 0.460, and have 3.4v.
d6950 removed and still the same.
i test all above without bil too.
 

2informaticos

Administrator
Staff member
If you get same diode mode reading on both line, I doubt to have bad solders, or broken traces under SMC; unless both lines broken.
Check resistance between pins 17/18 and 27/28 of U7000.
Be sure Q7055 is good; also check all traces in that area.
 

Yoel Ren

Member
its 3.5 ohm and 20.5 ohm.

q7055 and the traces are good...
i have measured smc_Reset_l is getting to the pad under smc.
 
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Yoel Ren

Member
change u7000 and r7000 resistance is good. but still 12.26v ppbus :(
magsafe light is orange instead of green, is it normal ?
 

2informaticos

Administrator
Staff member
Fan runs with normal speed?
Be sure the machine turns on in normal mode.
If it turns on in SMC bypass mode, PPBUS_G3H will remain 12.2V.
 

Yoel Ren

Member
when this came in board turn on, theres a jumper wire from one of the six traces beside c4905, if forget which one ( not present in boardview ), i remove the wire and intend to redo all of the work.
but when i test it now, only fan spin ( normal speed ), but no brain / capslock / usb activity, but seeing ppbus is 12.2v, i focus on that first.
 
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