A2251 MacbookPro 5v no boot

[lenni]

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 is 820-01949 and I found it here in the forum and I measured many voltages.

The scenario:
USB_C_T is the charger port with different behaviour (5V 0.1A)
For the following measurements I plugged the charger in one of the other ports (to get correct readings) USB_C_R.

1 PP20V_USBC_R_VBUS 5.11 V
2 PP3V3_UPC_R_LDO 3.37 V
2 PP1V5_UPC_LDO_CORE_R 1.58 V
3 HV_GATE1 / HV_GATE2 not found
4 PPDCIN_G3H 5.08 V
4 PPDCIN_G3H_CHGR 5.08 V
4 PPVIN_G3H_P3V3G3H 12.25 V
5 CHGR_VDDA 5.05 V
5 PPVDD_SE_VDDA 0 V
6 PPVBAT_G3H_CONN 0.21 V
7 PP3V3_G3H 3.31 V

The PP3V3_G3H looks normal, but it is 0V if the charger is connected to the faulty port.

I don't have a clue where to look next. Do you have hints or tips for me what to check next?

If needed I could also post images of the board.

[lenni]

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

[mon2]

Re: A2251 MacbookPro 5v no boot

Sounds like the one ACE controller will need to be replaced if not behaving the same as others but...

what is the voltage of PPBUS_G3H ?

Check & post the voltage of PPBUS_G3H when using a 'known good port'.

Then repeat with the 'defective' type C port.

[lenni]

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

[lenni]

Re: A2251 MacbookPro 5v no boot

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

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 V != 5V Produced from U7650/Q7660.
PP3V3_G3S 0 V != 3.3V Produced from U8210.
PP1V8_G3S 0 V != 1.8V Produced from U8220.

To sum it up, my voltages for PPVDDCPUSRAM_AWAKE and PPVDDCPU_AWAKE are to low. Could this lead to U7800?

[lenni]

Re: A2251 MacbookPro 5v no boot

I thought i found a boot up sequence for the CD3217 and T2 Mac here:
https://logi.wiki/index.php/CD3217_a...er_on_Sequence

In this sequence my board is struggeling from the PMU_VDDMAIN_EN.

PMU_VDDMAIN_EN = 0.1 mV - to low!
PP3V3_G3H = 3.31 V seems good
P3V3MAIN_PGOOD = 3.2 mV - to low!
PP3V_G3H_RTC = 3 V seems okay
PMU_CLK32K_PCH_R = 0.87 V okay
PCH_RTC_RESET_L = 3 V okay
P5VG3S_EN = 0.1 mV - to low!
PP5V_G3S = 0.3 mV - to low!
P3V3G3S_EN = 0.1 mV - to low!
PP3V3_G3S = 0.1 mV - to low!

The readings that are to low are refering to U7650.
I attached an image from this chip but to me it doesn't seems to look bad.

Do you share my opinion, that i should try to resolder or replace this chip?

[lenni]

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]

[lilkobe]

Re: A2251 MacbookPro 5v no boot

I thought i found a boot up sequence for the CD3217 and T2 Mac here:
https://logi.wiki/index.php/CD3217_a...er_on_Sequence

In this sequence my board is struggeling from the PMU_VDDMAIN_EN.

PMU_VDDMAIN_EN = 0.1 mV - to low!
PP3V3_G3H = 3.31 V seems good
P3V3MAIN_PGOOD = 3.2 mV - to low!
PP3V_G3H_RTC = 3 V seems okay
PMU_CLK32K_PCH_R = 0.87 V okay
PCH_RTC_RESET_L = 3 V okay
P5VG3S_EN = 0.1 mV - to low!
PP5V_G3S = 0.3 mV - to low!
P3V3G3S_EN = 0.1 mV - to low!
PP3V3_G3S = 0.1 mV - to low!

The readings that are to low are refering to U7650.
I attached an image from this chip but to me it doesn't seems to look bad.

Do you share my opinion, that i should try to resolder or replace this chip?

Hi Lenni,
I have almost the exact same readings, except all 4 ports reading the same 5v 0.1a.
What was the problem regarding your board at the end? Did you fix it?
Thanks Lil