This one came with a keyboard/trackpad failure. Everything else is working. The power button works.
Watched Louis' video, tested if holding Option key was helping but no change.
Started from the trackpad connector and found out that PP3V3_S4 was reading 2.1V.
Traced it to C2952 which was looking off, and replaced it. No change.
Found corrosion at Q2945, and replaced it. No change.
I went to every circuit that uses PP3V3_S4 as input and checked capacitors / resistors to find a short to ground or an abnormal value but nothing obvious.
Then I moved on to U8000 where PP3V3_S4 is created from PP3V3_S5, PP3V3_S5 is 3.3 V but PP3V3_S4_FET_R is 2.1V
So I am suspecting whether U8000 is not delivering the right voltage but I wanted to check before I blindly go ahead and change it. The chip looks healthy.
Watched Louis' video, tested if holding Option key was helping but no change.
Started from the trackpad connector and found out that PP3V3_S4 was reading 2.1V.
Traced it to C2952 which was looking off, and replaced it. No change.
Found corrosion at Q2945, and replaced it. No change.
I went to every circuit that uses PP3V3_S4 as input and checked capacitors / resistors to find a short to ground or an abnormal value but nothing obvious.
Then I moved on to U8000 where PP3V3_S4 is created from PP3V3_S5, PP3V3_S5 is 3.3 V but PP3V3_S4_FET_R is 2.1V
So I am suspecting whether U8000 is not delivering the right voltage but I wanted to check before I blindly go ahead and change it. The chip looks healthy.
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