820-00281 - A. Not powering on

[buritix]

Hello everyone.

I'm new in the forum, and I am not a native English speaker so just in case I make mistakes writing, i'm using google translate.
I hope to find some help here, thanks

PP20V_USBC_XA_VBUS = 5.207 v

PP3V3_G3H_REG_R= 3.418 v

PPVIN_G3H_P3V3G3H = 4.886 v

PPDCIN_G3H_CHGR_R = 5.197 v

PPBUS_G3H_R = 0.029 v

 

[2informaticos]

First of all, welcome to the forum!

Any history fault available?
Do you get the same behaviour on all 4 ports?
Compare diode mode readings on LDO outputs of all CD3215 chips; 1V1, 1V8, 3V3.
Be sure to use correct USB-C charger.

 

[buritix]

Thanks for the welcome.
- The board was with a voltage problem varying between 5v and 1v in PP20V_USBC_XA_VBUS in U3100 thus i replaced U3100 , after that is the actual condition

- Yes is the same behavior on all 4 ports now

- All 4 has similar values and 1v1 ,1v8 and 3v3 voltages are presents in UB300 and UB400 but in U3100 and U3200 are present 1v8 and 3v3 but 1v1 is 0v
and diodo mode in chips are
U3100 1v1 = 513.
U3200 1v1 = 495
UB400 1v1 = 516
UB300 1v1 = 517

- Yes i have a 87w original charger an works good in other macbook

 

[2informaticos]

Change U3200 first; check if 1V1 LDO appears then.

 

[buritix]

Change U3200 first; check if 1V1 LDO appears then.

Done i have already changed it and now in diodo mode 1v1 has 515 but it has the same behavior not 1v1 , in addition to that, i figured out that R3034 UPC_XB_HPD_RX and R3033 UPC_XA_HPD_RX has 0 ohm and the schematic shows that both 100kohms, i have already changed too for 100kohms , the board has the same behavior

 

[2informaticos]

Any reason to quote an entire text visible few centimeters above?
Do not hit Reply button, just write inside the down box.
Please, maintain forum aesthetic...

Did you really find R3033/34 in the board?
Appear like NO STUFF in the schematic; put back original ones.

Change U3100 now...