[First repair] First stage boot draws 300mA

Nintendo Questions
1

Hi everyone,

this is my very first repair attempt to an Erista board. Followed retrosix guide but I cannot get the 200mA current draw (no lcd) that should be observed during first stage boot.

PMIC readings are as follows:

SD3 VDD_CPU_1V8: 1.812V
SD2 VDD_1V3: 1.367V
SD0 VDD_CPU_1V0: 1.030V
SD1 VDD_CPU_1V1: 1.160V
LD08 VDD_1V05A: 1.05V
LD07 VDD_1V05A: 1.05V
LD03-5 VCC_3V3: 3.3V
LD04: VDD_1V0: 1.0V

My understanding is that all voltage that should appear during first stage boot are there.

Also EN chip delivers the 3.3V.

M92T36 was removed because pin 5 was shorted to ground. This removed 200mA of current draw but still not reaching the expected 200mA.

I have no access to an oscilloscope right now so cannot check for EMMC activity. (Hopefully) I will be soon be able to try and dump the NAND from another modded switch but I have not received the chip yet.

Am I doing it right ? Any recommandation/hints ?

2

I was able to dump the EMMC for another switch using an HFWLY chip so I would think this rules out bad EMMC (power consumption remains the same when the emmc is out anyway).

I was thinking of removing the cpu buck converter.

What do you think ?