Attempting to service this same iMAC pro with a 'no power' case. A few corrections.
Apple (Foxconn) DOES have a bank of DEBUG LEDs onboard. By default, they will not light up unless you press the tiny pushbutton that is just below the same row of LEDs.
If the first left LED enables with the pushbutton, then the power supply which is feeding the 12v rail is ON. Be very cautious of the high voltage near the exposed power supply. This unit is a shock hazard.
After some probing, we are facing that PP1V8_S5 is @ 0 volts. All rails from this and lower are at 0 volts. On a macbook, usually a DFU corrects the PP1V8_S5 rail. For us, even with numerous attempts using Configurator 2 and different USB cable, facing Error Code 9 on the DFU revive process. Currently stuck on this repair.
From our understanding, PP1V8_S5 is created by a leg on the PMIC @ U7800. Do not feel like replacing this complex PMIC nor know of reliable of sources for this part. The higher current BUCK3_LX0 leg IS WORKING. No short on the missing rail so may attempt a bypass.
Attempting to service this same iMAC pro with a 'no power' case. A few corrections.
Apple (Foxconn) DOES have a bank of DEBUG LEDs onboard. By default, they will not light up unless you press the tiny pushbutton that is just below the same row of LEDs.
If the first left LED enables with the pushbutton, then the power supply which is feeding the 12v rail is ON. Be very cautious of the high voltage near the exposed power supply. This unit is a shock hazard.
After some probing, we are facing that PP1V8_S5 is @ 0 volts. All rails from this and lower are at 0 volts. On a macbook, usually a DFU corrects the PP1V8_S5 rail. For us, even with numerous attempts using Configurator 2 and different USB cable, facing Error Code 9 on the DFU revive process. Currently stuck on this repair.
From our understanding, PP1V8_S5 is created by a leg on the PMIC @ U7800. Do not feel like replacing this complex PMIC nor know of reliable of sources for this part. The higher current BUCK3_LX0 leg IS WORKING. No short on the missing rail so may attempt a bypass.
Attempting to service this same iMAC pro with a 'no power' case. A few corrections.
Apple (Foxconn) DOES have a bank of DEBUG LEDs onboard. By default, they will not light up unless you press the tiny pushbutton that is just below the same row of LEDs.
If the first left LED enables with the pushbutton, then the power supply which is feeding the 12v rail is ON. Be very cautious of the high voltage near the exposed power supply. This unit is a shock hazard.
After some probing, we are facing that PP1V8_S5 is @ 0 volts. All rails from this and lower are at 0 volts. On a macbook, usually a DFU corrects the PP1V8_S5 rail. For us, even with numerous attempts using Configurator 2 and different USB cable, facing Error Code 9 on the DFU revive process. Currently stuck on this repair.
From our understanding, PP1V8_S5 is created by a leg on the PMIC @ U7800. Do not feel like replacing this complex PMIC nor know of reliable of sources for this part. The higher current BUCK3_LX0 leg IS WORKING. No short on the missing rail so may attempt a bypass.
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