(347) 552-2258 [email protected]

820-3208a liquid damage, no light on charger.

B

BigPersonalety

New member
Having trouble with this board, cant figure out why it's not working.
So
PP3V42_G3H - 3,42V (Working properly)
PPBUS_G3H - 8,2V (As i understand this means U7000 is not communicating with SMC?)
SYS_ONEWIRE - 1V (Nothing is connected to LIO)
SMC_BC_ACOK - 3,4V

Done so far:
Replaced R6905 (It was 190ohm when i got the board)
Replaced LCD connector (pins 3, 4 where corroded to oblivion)
Replaced C6996, C6997 (They were corroded)

Notes:
1) Charger is 100% working.
2) When plugging in this charger to charge other working macbook air, green light lights up for 1-2 seconds, then it turns into orange light and macbook starts to charger. Now after this, when i plug this charger into my board, light actually lights up but after some time it just fades away, never to come back. And to get it to light up again, you have to plug it in the working macbook air again.
3) Board looks very clean, only corrosion i found was near u6990 i properly cleaned it and replaced faulty components.
 
B

BigPersonalety

New member
Ops forgot, there was just a teeny tiny amount of green junk near U9410
All contacts look clean, but i am gonna clean it tomorrow. No time left for today.
Thanks for your help ;)
 
2informaticos

2informaticos

Administrator
Staff member
"SYS_ONEWIRE - 1V (Nothing is connected to LIO)"
Normal, SYS_ONEWIRE is pulled-up on LIO board.

"2) When plugging in this charger to charge other working macbook air, green light lights up for 1-2 seconds, then it turns into orange light and macbook starts to charger. Now after this, when i plug this charger into my board, light actually lights up but after some time it just fades away, never to come back. And to get it to light up again, you have to plug it in the working macbook air again."
This is normal behavior too; just a memory effect...

SYS_ONEWIRE circuit is entirely located on the LIO board.
Take this schematic as example and check U6900/01.
https://drive.google.com/open?id=1b0wd4sOL4JmAQIDXma69914-LBxasJvx

First of all check basic SMC power rails and signals (SMC_RESET_L, etc), 3V3_SUS, 3V3_S5...
 
B

BigPersonalety

New member
Here you go
SMC_RESET_L - 3.16V
PP3V3_SUS - 0V (Measured at C6100, no short to ground)
PP3V3_S5 - 0,26V (Measured ar R7956, 150kOhms)

Did this very quickly before work, Will update this closer to evening. I am located in EUROPE,
Thanks!
 
B

BigPersonalety

New member
Okey...
so from what I figured out line from u6900 to charger was broken, I restored it but still no green light.
voltage on sys_onewire and line to adapter from u6900 (line that was broken) are both 3,4V
i think it’s something deeper, tho have no idea
 
2informaticos

2informaticos

Administrator
Staff member
"U4900 block (2 of 2), page 40"
That SMC block has more pins for power and signals...

Check PCH's RTC signals too.
C1802/3 fail a lot on this board...
 
B

BigPersonalety

New member
SMC (2 of 2)
PP1v2_S5_SMC_VVDC - 1,2V
SMC_RESET_L - jumping 3,26-3,28V
SMC_WAKE_L - 2,92V
SMC_TCK - 3,46V
SMC_TMS - 3,46V
SMC_TDO - 3,46V
SMC_TDI - 3,46V
PP3V3_S5_SMC_VDDA - 3,42V
PP3V3_S5_AVREF_SMC - 3,3V
GND_SMC_AVSS - shorted to ground
 
B

BigPersonalety

New member
Reballed SMC
Got orange light on charger, tho no fan spin -_-

update:
tried resetting SMC - didn’t help
PP5V_S0 - 0V
 
Last edited:
B

BigPersonalety

New member
When I plug charger in, it first lights up green, then after 2-3 seconds turn orange.
PPBUS_G3H - 8,4V
PP3V3_SUS - 0V (not shorted to ground)
PP3V3_S5 - 3,3V
 
2informaticos

2informaticos

Administrator
Staff member
OK, SMC runs now.
Do you get PM_SLP_SUS_L?

You didn't check all RTC signals; still missing PCH_iNTRUDER_L and PCH_INTVRMEN.
32KHz comes out from U2700?
 
B

BigPersonalety

New member
PM_SLP_SUS_L - 0V (R7917, R7930 are missing, is This Ok?)
PP3V3_S5 - 3,3V
PCH_INTRUDER_L - 2,9V
PCH_INTVRMEN - 3V
32khz comes from u2700
 
Last edited:
2informaticos

2informaticos

Administrator
Staff member
All the components marked "NO STUFF", are not present...

Check PCH's block "System Power Management", at page 17.
Post SMC_ADAPTER_EN, PM_BATLOW_L, PCH_DSWVRMEN, PM_DSW_PWRGD.
 
You must log in or register to reply here.
Top