820-01700 20v 0.05a

[No-Clean]

Board had minor corrosion around L9580 C9586 was shorted, removed it and short is gone but now it is stuck at 20v 0.05a, tried flashing/reviving T2 but comes up with errors all the time.

Checked all power FETs and they are all fine.

PPBUS 12.6V
PP2V5_NAND_SSD0 2.5v
PP1V8_G3S present
PP5V_G3S present
PP3V3_G3H_T present
PP3V3_G3H_SSD0_SNS present

 

[2informaticos]

Board doesn't try to start at all?
Did you test in SMC bypass mode?
Check if all SLPS2R and AWAKE voltages are present.

 

[No-Clean]

I measured the missing rails while I connected the charger and they don't even pulse once, the meter shows 5V, then 20V at 0.15a then goes down to 20V 0.08a then 0.05a and stays there.

SMC bypass was tried but same result.

SLPS2R and AWAKE signals present.

 

[2informaticos]

Be sure to use the second machine with the same macOS as in the T2 machine.

 

[No-Clean]

This amigo is a great tip, I have not tried that and the customer just told me he has Big Sur and I was trying the T2 firmware with a Catalina Machine.

Question for future reference, will it work if say I have Big Sur on the working machine and Catalina on the non working one?

 

[2informaticos]

Must be the same macOS on both machines.
Try all options.
Someone in the forum mentioned a Mac Mini from 2020 which came with Mojave!!!

 

[No-Clean]

I will have to send @2informaticos a present with Santa this Christmas, thanks for helping, I installed Big Sur on another USB-C mac and restored T2 firmware, Mac is now back to life.

Thanks and happy holidays!

 

[2informaticos]

You're welcome, glad to hear is solved.

 

[No-Clean]

Just for feedback, today I got another 2018 stuck at 5v after checking the board for problems found nothing wrong and decided to restore T2, I did it from the Big Sur machine and it failed, then I did it from another Mac with USB-C and Catalina and it worked, so when restoring T2 firmware make sure the OS matches that of the faulty Mac.