Hi I'm new to the forum and hoping to learn a bit along the way.
I recently purchased an old water damaged macbook to help me learn a bit more about electronic, schematics and board views.
I have managed to get around a lot of problems. I have it turning on and even charging now. The only problem Im seeing at the minute is the trackpad.
I just can't understand the trackpad circuit.
I finally realised I'm missing the 18.5v on the Trackpad connector J5800, which lead me to U5701 which has power but I noticed pin 21 was missing 18.5v.
USB_TPAD_P was present at R5701=3.1v
But
USBTPAD_N was 0v
Which somehow lead me to U5805
which is missing 5v power in the entire region.
This is were I'm getting really confused I think I'm supposed to be getting power from L5800 and C5800 which are both missing from my board.
I was starting to think somebody removed them but the pads look normal, OK some corrosion but doesn't look like parts were removed.
I then managed to find photos online of my exact model and they are all missing these parts too, but the schematics and board views for my model all show these parts and I really can't understand how U5701 is supposed to function without the 5volts that would be fed by the missing components.
My board is the 2012 i7. 2.9GHz
A1278 820_3115_B
The only schematic I can find is the
A1278 820_3115_B MLB, J30
But this clearly is the wrong schematic as at a glance is missing the following components. I have a feeling its just the i7 versions that have a different layout.
Anyway I would appreciate if anyone could explain this to me.
Thanks
All missing
R7803
C5800
L5800
R4515
R5015
R2704
C7800
I recently purchased an old water damaged macbook to help me learn a bit more about electronic, schematics and board views.
I have managed to get around a lot of problems. I have it turning on and even charging now. The only problem Im seeing at the minute is the trackpad.
I just can't understand the trackpad circuit.
I finally realised I'm missing the 18.5v on the Trackpad connector J5800, which lead me to U5701 which has power but I noticed pin 21 was missing 18.5v.
USB_TPAD_P was present at R5701=3.1v
But
USBTPAD_N was 0v
Which somehow lead me to U5805
which is missing 5v power in the entire region.
This is were I'm getting really confused I think I'm supposed to be getting power from L5800 and C5800 which are both missing from my board.
I was starting to think somebody removed them but the pads look normal, OK some corrosion but doesn't look like parts were removed.
I then managed to find photos online of my exact model and they are all missing these parts too, but the schematics and board views for my model all show these parts and I really can't understand how U5701 is supposed to function without the 5volts that would be fed by the missing components.
My board is the 2012 i7. 2.9GHz
A1278 820_3115_B
The only schematic I can find is the
A1278 820_3115_B MLB, J30
But this clearly is the wrong schematic as at a glance is missing the following components. I have a feeling its just the i7 versions that have a different layout.
Anyway I would appreciate if anyone could explain this to me.
Thanks
All missing
R7803
C5800
L5800
R4515
R5015
R2704
C7800
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