820-2915-a Spontaneous Shutdown, No Startup

JustAnotherGuy

New member
I have a 820-2915-a (2011 MacBook Pro 15) that was running a memtest86 when it spontaneously shutdown. It will not start up again. The power connector stays green, even though the battery is at ~10% charge.
SMC reset does not work.
SMC bypass does not work.
Left battery disconnected overnight, then plugged in power cable: no fan spin.
Plugged in after disconnected all peripherals from logic board except fans: no fan spin.
No water damage.
Logic board was replaced by Apple maybe... 4 years back? For GPU failure.

Probed the following:
PPDCIN_G3H - 16.7V
PPBUS_G3H - 12.5V
PP3V42_G3H - 3.48V
PPVRTC_G3H - 3.4V
PP5V_S5 - pulsing 0-5V ~2Hz
PP5V_SUS - pulsing 0-5V
PP3V3_S5 - pulsing 0-3.5V
PP3V3_ENET - 0V
PP3V3_S5_AVREF_SMC - 3.3V
PP3V3_S5_SMC_AVCC - 3.5V
PP3V3_S5_EN - pulsing 0-3.5V
SMC_PM_G2_EN - pulsing 0-3.5V
S5_PWRGD - pulsing 0-3.4V
SMC_RESET_L - 3.4V
SMC_ADAPTER - pulsing 0 - 3.46V
PM_SLP_S5_L - 0V
G3_POWERON_L - 0V

My best guess is SMC or TPS51980? Any ideas if I am on the right track / have the right issue nailed down? I don't want to blindly jump into replacing the SMC if I don't have to... it looks like a pain.

Thanks.
 

2informaticos

Administrator
Staff member
First of all, welcome to the forum!

Be sure to use original 85W charger.
Battery should charge even in off state.
If Magsafe stuck in green light, there may be a problem with SMC, or battery.

Check diode mode to ground on all big coils; starting with L7220/60.
 

JustAnotherGuy

New member
Thanks!

I am using the original charger that came with the laptop (its a new one that apple replaced cause my old one frayed).

The battery was replaced at the same time as the motherboard so it is relatively new; also I don't have that many cycles on it (maybe 100?) It does not charge at all. I left it plugged in for about 2 hours and the MagSafe stayed green the whole time and the battery indicator light did not change.

I will check the coils.
 
Last edited:

2informaticos

Administrator
Staff member
Please write directly on the Reply Box.
I don't see a real reason to quote an entire post, visible few centimeters above.
Please, maintain forum aesthetic.

Check voltage and diode mode to ground at SCL/SDA lines of battery bus.
Disconnect BIL and see if starts charging.
 

JustAnotherGuy

New member
DIODE
L9701 - 0.426 V
L7220 - 0.001 V
L7260 - 0.138 V
L7550 - 0.006 V
L7510 - 0.007 V
L7520 - 0.007 V
L7530 - 0.007 V
L7630 - 0.022 V
L9560 - 0.033 V
L9510 - 0.122 V
L7330 - 0.457 V
L8920 - 0.006 V
L3895 - 0.522 V
L7770 - 0.330 V
L7720 - 0.228 V

Battery
SCL - 0.524V (diode) 3.473V (volt)
SDA - 0.522V (diode) 4.473V (volt)

Disconnecting battery indicator light seems to have no effect, still not charging (MagSafe stays green).
 

2informaticos

Administrator
Staff member
"L7220 - 0.001 V"
There is a short circuit.
Left the coil one side and check where the short remains.
 
Last edited:

2informaticos

Administrator
Staff member
Pure short to ground on 5V_S3 power rail.
Voltage injection method will help you to find the culprit.
Read more on the forum, before applying voltage.
 
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