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820-3115 trackpad doesn't track

Jay

Jay

Member
820-3115 came in as no power. Replaced U7200 and power was restored.
Intermittent keyboard and trackpad only clicked, didn't track. Light on MagSafe would be green for 10 sec, then off for a few sec, then back to green.
Replaced U5701 and keyboard is now 100%, MagSafe LED also acts normal now. Still no tracking on the trackpad though. USB keyboard/mouse also intermittently didn't work,
Finally replaced U2700 as I get 0V on R5702. USB is now acting normal but this made no difference for the trackpad. tested with two other trackpads that show the same issue.

Not sure where to take it from here.
Board did not suffer liquid damage.
 
Jay

Jay

Member
J5800 diode mode all pins

1: 0v
2: 0v
3: 0.681v
4: 0.682v
5: 0.682v
6: 0.682v
7: 0.681v
8: 0.681v
9: 0.655v
10: 0.680v
11: 0.680v
12: 0.680v
13: 0.680v
14: 0.931v
15: 0.681v
16: 0.681v
17: 0.446v
18: 0.L
19: 0.L
20: 0.688v
21: 0.520v
22: 0.359v
 
D

dukefawks

Administrator
Pin 19 has nothing to do with the trackpad working or not, it is for thermal sensor, should be fixed though. Pin 18 is a big problem as there should be something there. Corroded trace to R5800, R5800 fucked, etc.
 
Jay

Jay

Member
R5806 is present.

No R5800 on this board but checked L5800 and C5800 (assuming you made a typo) and those are not on the board. According to schematic they should be there? It doesn't mention OMIT or NOSTUFF but the pads have not been used, checked a few donor boards and they don't have those components either. No tin, scrapes or pits, just unused gold contacts.

I do get 5V where those components should be according to schematic. If none of the donor boards have them either I'm assuming the schematic is wrong here, what do you think?
 
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