[SOLVED]820-2849 Trackpad click / no movement

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MOberdick

New member
So I have a 17" Pro here that has minor water damage near the trackpad but doesnt appear to have gone near the board. I replaced the trackpad as well as the cable twice and the trackpad is registering a click just fine but the cursor doesnt move. I have tried external bootables and verified the new parts work in other machines. I have no known-good boards or even doner boards of this model to compare to but here are the diode mode measurements for each pin on the connector and I was hoping someone could provide me with the correct readings to compare to or if there should be something else i should be looking at first.

Starting from Top left -> Top Right and then Bottom left -> bottom right

TOP

Pin 1 - .332
Pin 2 - .705
Pin 3 - .693
Pin 4 - .694
Pin 5 - .957
Pin 6 - .694
Pin 7 - .694
Pin 8 - .693
Pin 9 - .693
Pin 10 - .694
Pin 11 - 0.00

BOTTOM

Pin 1 - .699
Pin 2 - .466
Pin 3 - .435
Pin 4 - .694
Pin 5 - .693
Pin 6 - .692
Pin 7 - .666
Pin 8 - .693
Pin 9 - .693
Pin 10 - .694
Pin 11 - 0.00
 

bjf

Member
I'm guessing damage to the 18.5V trackpad boost circuit - either not creating it or it's not getting to the trackpad. I can't remember offhand if this model uses that, but I'm pretty sure it does. I'm not near a schematic but it should be easy to find.
 

MOberdick

New member
PP18v5 is actually not present.. starting to troubleshoot and noticed pp5v_s3 is shorted.. Checking around U7201 now
 

dukefawks

Administrator
Check if Z2_BOOST_EN is high if yes then probably dead U5805. Did you check 18V at L5801 to rule out a corroded trace to trackpad connector?
 
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