Macbook A1989, 820-00850, won't boot

ipetro

Member
consumption 5 V 0.35A
Here are my measurements on this board:
  • UB300
    5V on [p:FB200:1]=5v
    3V3 on [p:CB308:1] =3.34v
    1V8 on [p:CB305:1]=1.795v
    1V8 on [p:CB306:1]=1.8v
    1V1 on [p:CB304:1]=1.12v
  • UB400
    5V on [p:FB201:1]]=5v
    3V3 on [p:CB408:1]=3.34v
    1V8 on [p:CB405:1]=1.8v
    1V8 on [p:CB406:1]=1.8v
    1V1 on [p:CB404:1]=1.12v
  • U3100
    5V on [p:F3000:1]=5v
    3V3 on [p:C3108:1]==3.34v
    1V8 on [p:C3105:1]=1.796v
    1V8 on [p:C3106:1]=1.8v
    1V1 on [p:C3104:1]=1.12v
  • U3200
    5V on [p:F3001:1]=5v
    3V3 on [p:C3208:1]=3.34v
    1V8 on [p:C3205:1]=1.8v
    1V8 on [p:C3206:1]=1.796v
    1V1 on [p:C3204:1]=1.12v


  • P3V3_UPC_XA_LDO=3.34v
  • P1V8_UPC_XA_LDOA=1.8v
  • P1V8_UPC_XA_LDOD=1.795v
  • P1V1_UPC_XA_LDO_BMC=1.12v

    P3V3_G3H_RTC=3.38v


    PBUS_G3H=12.31v

 
Last edited:

2informaticos

Administrator
Staff member
Please, use ONLY schematic points to specify readings.
You made very difficult to read this post.
A lot of readings, which don't help too much.

My first question, all USB-C ports have the same behavior?
AUX_DET should have 1.25V aprox; did you inject 5V there?
Not sure what mean the readings bellow "20V switch over..."; did you inject 20V on the board?

BTW, do not use "V" when you post diode mode readings.
 

ipetro

Member
Please, use ONLY schematic points to specify readings.
You made very difficult to read this post.
A lot of readings, which don't help too much.

My first question, all USB-C ports have the same behavior?
AUX_DET should have 1.25V aprox; did you inject 5V there?
Not sure what mean the readings bellow "20V switch over..."; did you inject 20V on the board?

BTW, do not use "V" when you post diode mode readings.
I apologize if I’m doing something wrong or asking stupid questions, I’m not experienced and I’m a newbie.
I will try to take into account your wishes.
If you put the board in the MacBook and connect it to the battery, it switches to 20V 0.00A and nothing happens, it doesn’t boot. If you then take it out on the table, the indicators and behavior on all four ports are identical.
CHGR_AUX_DET=1.25v
 

ipetro

Member
if you leave the board connected to charging for a while, the readings will fluctuate 5.080-5.087v and 0.276 -0.298a
 

2informaticos

Administrator
Staff member
Check SLPS2R and AWAKE voltages around U7800.
Be aware, puting the Mac in DFU is not simple as you think.
You may need to force it, with wires method.

Any reason to quote an entire post, visible few centimeters above?
Please, maintain the forum aesthetic...
 
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