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820 00165 fan spins for 1 second then turns off, taking 25mA not entering S4 state

R

Roan

Member
No short on PP3V3_S4 pin on the TPS51980 EN present and VIN present. Maybe short on PP3V3_S4 since the voltage is 0.31V instead of 3.3V?
 
2informaticos

2informaticos

Administrator
Staff member
Fan is powered from 5V_S0, so more S0 voltages should pulse at least (in that second).
Check for pulse at all big coils.
Also check all power rails from pages 57/58.
Where is no pulse, check diode mode to ground...
 
R

Roan

Member
Checked around, all big diodes had pulses and when I came acros PP3V3_S4 it turned on. Now pulling 300-500 mA. Something around DCIN board not connected properly?
 
R

Roan

Member
It turns on after I first pressed the power button, then release then press again for long enough to make the backlight come on (releasing when hearing the chime makes the mac shutdown directly)

it is also very slow, will try to install new os via pendrive today, but the above behaviour looks like an SMC issue. Already tried SMC reset, is checking a sensor a good idea? (no high fan though)
 
2informaticos

2informaticos

Administrator
Staff member
Did you try PRAM reset?
Are you using original Magsafe 2 charger?

Disconnect trackpad and see if starts normal using R5115/16 pads instead of power button.

You can try clean ME BIOS, just in case.
 
R

Roan

Member
Tried Pram reset, got a big white flash, this is something I have not experienced before so maybe it's not what it is supposed to do
Original magsafe 2 charger with power brick attatched and one connected to power supply with 19.5V 2A

Disconnecting trackpad and using the pads gives the same behaviour

Cleaned the ME no result, will flash new bios today
 
R

Roan

Member
new BIOS and still the Mac is very slow and has weird startup issues as mentioned before. It also looks to shutdown when it should go to sleep
 
R

Roan

Member
replacing all 4 boards/flexes does not change anything. Now trying to use USB macOS, but it has had a full loading bar for 4+ hours now. Also the slowness is noticable before entering any os. Also in the Catalina Installer for instance
 
2informaticos

2informaticos

Administrator
Staff member
Did you clean ME region correctly for sure?
Can you load Linux, or Windows Live USB?
 
Last edited:
R

Roan

Member
Closing the lid still makes it shutdown. Powering on takes one normal press till the fan stops spinning, then one long ~5second press until the chime comes and the backlight turns on. I can only release the power key after the backlight turns on, releasing on chime makes it shutdown again.
 
R

Roan

Member
after removing R1921 is gives 0.05V, something to worry about? its not low as in 0 but also not 0.9 or 3.3
 
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