I'm working on a 2016 MacBook Pro A1706 with touchbar, 820-00239 logic board. The board seems to power on and takes about 700 mA from the USB-C port, the CPU gets warm, the trackpad clicks, but there is no chime and the caps lock light doesn't turn on.
The board is in good condition and there is no signs of liquid damage or any damaged components.
I've tried flashing a different BIOS - I'm not 100% sure if the file I flashed was good or if there is ME Region issues, but there was no change in the behavior at all. The SPI termination resistors all seem to be okay.
All voltages seem to be present except both PPVCCGT_S0_CPU, which I think is normal based on reading other posts, and PPVCCEDRAM_S0_CPU, which I'm assuming is the problem. PPVCCEDRAM_S0_REG_R and _REG_F are both 1.05 V.
PPVCCEDRAM_S0_CPU doesn't seem to be shorted, it measures about 100 ohms/0.100 in diode mode. I don't have another similar board to compare this to.
PPVCCEDRAM_S0_CPU voltage seems to be controlled by PM_OPC_ZVM_L and should be turned on when PM_OPC_ZVM_L is high (?). This comes from a level shifter, U7790 which should shift CPU_ZVM_L up to 3.3 V.
The power voltages around U7790 and U7760 all seem to be okay: PP1V0_S3, PM_SLP_S3_L, and PP5V_S0. R7792 measures okay as well.
Both CPU_ZVM_L and PM_OPC_ZVM_L measure 0 V. Diode mode reading for CPU_ZVM_L is 0.295 and PM_OPC_ZVM_L 0.530.
Since CPU_ZVM_L comes directly from the CPU, I'm wondering if it's a bad CPU, but I'm not sure if there is something else that could be causing this CPU output to be low. I haven't tried to remove U7790 yet because it's right below the CPU.
If anyone has any suggestions for further troubleshooting, or if I've misunderstood some of these circuits, your help would be much appreciated! Thanks!
The board is in good condition and there is no signs of liquid damage or any damaged components.
I've tried flashing a different BIOS - I'm not 100% sure if the file I flashed was good or if there is ME Region issues, but there was no change in the behavior at all. The SPI termination resistors all seem to be okay.
All voltages seem to be present except both PPVCCGT_S0_CPU, which I think is normal based on reading other posts, and PPVCCEDRAM_S0_CPU, which I'm assuming is the problem. PPVCCEDRAM_S0_REG_R and _REG_F are both 1.05 V.
PPVCCEDRAM_S0_CPU doesn't seem to be shorted, it measures about 100 ohms/0.100 in diode mode. I don't have another similar board to compare this to.
PPVCCEDRAM_S0_CPU voltage seems to be controlled by PM_OPC_ZVM_L and should be turned on when PM_OPC_ZVM_L is high (?). This comes from a level shifter, U7790 which should shift CPU_ZVM_L up to 3.3 V.
The power voltages around U7790 and U7760 all seem to be okay: PP1V0_S3, PM_SLP_S3_L, and PP5V_S0. R7792 measures okay as well.
Both CPU_ZVM_L and PM_OPC_ZVM_L measure 0 V. Diode mode reading for CPU_ZVM_L is 0.295 and PM_OPC_ZVM_L 0.530.
Since CPU_ZVM_L comes directly from the CPU, I'm wondering if it's a bad CPU, but I'm not sure if there is something else that could be causing this CPU output to be low. I haven't tried to remove U7790 yet because it's right below the CPU.
If anyone has any suggestions for further troubleshooting, or if I've misunderstood some of these circuits, your help would be much appreciated! Thanks!
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