820-3115-B no green light, turns on for 30 secs then shuts down

Sr. Robot

Member
No visible corrosion, boots to OS with fan full speed then shuts down after about 30secs-1min. Also shuts down with everything disconnected.

PPBUS_G3H: 12.24v

PP3V42_G3H: 3.5v

PP5V_S5: 5v

PP5V_SUS: 0v

PP3V3_S5: 3.3v

PP3V3_SUS: 0v

PP3V3_S4: 1.5v

PP3V3_S3: 0v
 

2informaticos

Administrator
Staff member
Did you try known good trackpad board/cable?
It can be a reason for full speed fan.
Does the fan spins to max from moment zero, or increases speed in 15-20s?

The above mentioned voltages took with machine turned on?
 

Sr. Robot

Member
It stills shuts down without trackpad connected.

It takes about 2.5 secs to spin the fan, and it goes to max from momento zero.

Voltages taken with machine turned off after it shuts down. Not enough time to take voltages with it turned on.
 

2informaticos

Administrator
Staff member
You can take some voltages readings in 30s, for sure.
At least checking the big coils.
Restart it, if need more time to check another points.

Do you get correct AVREF_SMC?
 

Sr. Robot

Member
Voltages with board turned on:

PPBUS_G3H: 12.24v

PP3V42_G3H: 3.5v

PP5V_S5: 5.06v

PP5V_SUS: 5v

PP3V3_S5: 3.3v (not steady, it drops a lot)

PP3V3_S5_AVREF_SMC: 3.3v

PP3V3_SUS: 3.3v

PP3V3_S4: 3.3v

PP3V3_S3: 3.3v

PP1V8_S0: 1.8v

PP1V5_S3 : 1.5v

PP1V5_S0: 1.5v

PPVCORE_S0_CPU: 0.8v
 

2informaticos

Administrator
Staff member
0.8V on CPU looks good; if drops from 1.15V initial.
However, you have a problem with SMC, or some of its signals; because PPBUS_G3H isn't controlled.
Check voltage and diode mode to ground at SCL/SDA lines of battery bus.

Remove internal HDD and test if stays on with USB macOS.
You can also test in boot menu.
 
Last edited:

Sr. Robot

Member
Its showing very unstable behaviors. At first it didn't shut down with macos usb (i even installed catalina from usb and it didnt shut down), but now it shuts down with catalina and capitan install usb´s.

At some point i thought the wifi was causing the shutdowns since every time i tried to connect to wifi it shut down, so i disconnected the wifi cable and it started to show green light and regular fan spin (maybe just a casualty). But now its back to fast fan/dim green light.

Diode mode to ground:

SMBUS_SMC_5_G3_SCL: 0.455

SMBUS_SMC_5_G3_SDA 0.455
 

2informaticos

Administrator
Staff member
Did you test it disconnecting internal HDD?
Did it boot to USB macOS with normal fan speed?

Try known good trackpad cable/board.
Test again disconnecting webcam.
 

Sr. Robot

Member
Yeah, i disconnected internal HDD
No, still full fan speed.

Tried it, no difference.
No difference with webcam disconnected.
 
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