Re: A2251 MacbookPro 5v no boot

I have new findings.
I checked some capacitors near the Connector USBC_T ("bad").
I measured with no power the resistance on both pads.

The capacitors C3060 and C3108_T both have GND on both sides. This should mean i have to replace both because they are bad.

[if i power the board and measure the voltage on both pads i get 3.3V for PP3V3_UPC_T_LDO]

Re: A2251 MacbookPro 5v no boot

I thought i found a boot up sequence for the CD3217 and T2 Mac here:
[url]https://logi.wiki/index.php/CD3217_and_T2_Power_on_Sequence[/url]

In this sequence my board is struggeling from the PMU_VDDMAIN_EN.

PMU_VDDMAIN_EN = [COLOR="Red"]0.1 mV - to low![/COLOR]
PP3V3_G3H = 3.31 V seems good
P3V3MAIN_PGOOD = [COLOR="red"]3.2 mV - to low![/COLOR]
PP3V_G3H_RTC = 3 V seems okay
PMU_CLK32K_PCH_R = 0.87 V okay
PCH_RTC_RESET_L = 3 V okay
P5VG3S_EN = [COLOR="red"]0.1...

Re: A2251 MacbookPro 5v no boot

I found a power up sequence from a similar board here: [url]https://repair.wiki/w/A2179_2020_MacBook_Air[/url]

My readings are:
PP1V8_SLPS2R 1.8 V
PP1V8_AWAKE 1.8 V
PP1V8_SLPS2R_PMUGPIO 1.8 V
PP1V1_SLPS2R 1.1 V
PP0V8_SLPS2R 0.8 V
PP0V82_SLPDDR 0.82 V
PP3V3_AWAKE 3.31 V
PPVDDCPUSRAM_AWAKE 0.8 V != 1.06V Produced from U7800
PP0V9_SLPDDR 0.9 V
PP1V1_SLPDDR 1.1 V
PP1V2_AWAKE 1.2 V
PPVDDCPU_AWAKE 0.75 V != 1.06V Produced from U7800

PP5V_G3S 0...

Re: A2251 MacbookPro 5v no boot

my two readings are:

charger connected to "good" port#: PPBUS_G3H = 12.26 V
charger connected to "bad" port: PPBUS_G3H = 0.96 V

Re: A2251 MacbookPro 5v no boot

I just checked all 4 fuses
F3100_T 0.4 ohm
F3100_R 0.4 ohm
F3100_W 0.4 ohm
F3100_X 0.4 ohm

Hi,

I got a MacbookPro 13" 2020 A2251 and it doesn't show any vital signs. No fan, no boot up sound, no dfu, nothing. There is no liquid damage and no corrosion.

I noticed that the Voltage at all 4 USB-C ports is 5V and not 20V. I deep dived into the forum and learned, that the 4 USB-C controller chips CD3217 could have a problem.

My finding is that 3 / 4 ports show 5V and 0.33A when I plug the charger in. The last port shows 5V and 0.1A. This indicated to me that this is the faulty CD3217 chip (or anything in its area).

The board layout...

Re: New Members - please post your introductions here

Hi everyone,

my name is Lenni and I'm a graduate engineer for electrical engineering from germany. My hobby is to repair broken technical stuff. I found the way to this forum because I have a new challenge. I want to repair a bricked MacBook Pro and hope for some help from experienced users.