820-00850 not powering up

[iClub]

Good morning, this Mac intermittently switches on, and often does not. The restoration of the T2 was done, but it didn't have any effect. There are no signs of oxidation.

Voltage:
PPbus 12.62V;
PMU_ONOFF_L 0.8V;
CHGR_RST_IN_R 0V.
CHGR_RST_IN 0V, pulseless.
UPC_PMU_RESET 0V, 90mV;
PP3V3_G3H 3.36V

diode:
CHGR_RST_IN 0.630
CHGR_RST_IN_R 0.598
UPC_PMU_RESET 0.698

 

[2informaticos]

"PMU_ONOFF_L 0.8V"
Disconnect Touch ID and check again.
There should be 3V.

 

[iClub]

I've already tested with the peripherals disconnected.

 

[2informaticos]

Check R8015 ohm value.
Also post diode mode to ground at PMU_ONOFF_L.
Remove R4911 and check again.

 

[iClub]

R8015 9.89K Ohm.
PMU_ONOFF_L 0,693V
After removing R491 the PMU_ONOFF_L became 3.3V.

 

[2informaticos]

Resolder R4911, remove C4955 and check PMU_ONOFF_L again.

 

[iClub]

PMU_ONOFF_L 3.38V.
The machine does not show an image, but the processor heats up as if working and the trackpad works with the click.

 

[2informaticos]

Did you test for USB activity and external video?

 

[iClub]

No USB activity and no video on the outside, even with the display disconnected.

 

[2informaticos]

Reconnect Touch ID and check if PMU_ONOFF_L is good now.

 

[iClub]

The mac turns the cooler and stops. The external SSD turns the light on and off.

PMU_ONOFF_L 3.3V

 

[2informaticos]

"this Mac intermittently switches on, and often does not"
Did you mean it was working sometime?
Or just turned on, but no activity?

 

[iClub]

In the start the Mac turn on then we clean CD3215 because has dirt.
Now the Mac don't turn on.
We already test the peripherals and all are working fine

 

[2informaticos]

Please clarify, do not confuse turn on with working state.
Did you get image before cleaning it?

 

[iClub]

Did you get image before cleaning it?

Yes, I informed this at the beginning of the post, we activated the Mac after doing the t2, I tested all functions and did not identify any defect. When the machine is turned off and when I try to turn it on again it doesn't turn on, the external SSD light turns on without blinking, it doesn't give any image on the external or on the display. I notice that the Fan accelerates and turns off.

 

[2informaticos]

What is the voltage on USB-C input now?

 

[iClub]

I don't have the USB-C Amp Meter device yet.

 

[2informaticos]

But you can still measure voltage at R7020...

 

[iClub]

PPDCIN_G3H 20.42V

 

[2informaticos]

Something happened in the cleaning process.
Check for knocked off components first.
Reball/change CD3215 chips.