820-3435 - sometime the board doesnt power up with battery plugged.


the board had prior repair attempted. the board was liquid damaged and was missing an SMC.

if I use charger only, the board always turn on fine.
if I put a charged battery. turn it on, fan spins, use it as normal, it can charge the battery, passed ASD EFI and ASD OSX.
then a couple of hours later the board doesn't turn on. no fan spin. plug MagSafe 2 and it still doesn't turn on.
I'll have to unplug the battery and replugging the battery then the board can turn on.

the keyboard is good, the trackpad is good, MagSafe IO board and flex are good.
same thing without inside the housing.

original MagSafe 2.
I've tried another known working battery.

I've replaced SMC, U7090, D7005. ISL6259 and U7090 so far.

17/18 = 2.7ohms, 27/28 = 20.6ohms on ISL6259.
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Staff member
Post basic power on signals when the board doesn't want to turn on.
Be sure all RTC signals are steady.
Maybe crap accumulated underneath CPU; try to burn it heating CPU with quality flux.


what can it be,

so I charged up 100% at midnight 12 am, then turn it off and when I open in the morning around 10 am. it has 90% of battery life.

I've checked L3095, L7701, L7520, L7320, L7310, L7630, L7430 and they're not consuming power after turning off.

i haven't had the chance to measure basic power-on signals when the board doesn't want to turn on yet..


Staff member
Be sure no 3V3/5V_S3 voltage remains when board is turned off.
Also no S5 voltage is allowed if charger is disconnected.


battery only measurement.

PP5v_s5 - 0v
PP5V_S4RS3 - 0v
PP5V_S0 - 0v
PP3V3_S5 - 0v
PP3V3_SUS - 0v
PP3V3_S3 - 0v
PM_SLP_S0_L - 0.057v
PP3V3_S0 - 0.058v
PP3V3_S4SW_SNS - 0v
PP1V8_S3 - 0v
PP1V2_S3 - 0v

PP3V3_S0 - 0.058v is this normal when the board is turned off and the charger is disconnected

i dont know what else to check,
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Staff member
On battery alone, only 3V42_G3H and VRTC are present.
If battery is good for sure, check around U1900; change it, just in case.
PCH can also cosumes too much on VRTC, if nothing else is suspect.