LC 475 Pad repair

Scout

New Tinkerer
Apr 13, 2022
10
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I am needing to repair C149. I see where it connects to what the schematic says is pin 32 although that is not what I count it out to be. But my big issue is the via. Where does it go? I checked the back and it seems to be a dead end. There is a test point referenced on the schematic. I know nothing about test points so I am not sure what this connection need to be. Drawing of missing pad attached. Appreciate any guidance.
 

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  • LC 475 C149.pdf
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Nycturne

Tinkerer
Dec 18, 2024
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I am needing to repair C149. I see where it connects to what the schematic says is pin 32 although that is not what I count it out to be. But my big issue is the via. Where does it go? I checked the back and it seems to be a dead end. There is a test point referenced on the schematic. I know nothing about test points so I am not sure what this connection need to be. Drawing of missing pad attached. Appreciate any guidance.
Test points are vias or pads that can be used with multimeters or other test equipment to check signals or continuity. They are just points in the circuit that can be tapped into. In the case of the 475, the via is the test point.
 
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Scout

New Tinkerer
Apr 13, 2022
10
0
1
CA
Since it's the negative pad that's come off the board, you should be able to get away with tying that side of the capacitor into any other nearby ground.
The schematic shows it connecting to pin 32 which says "bypass". The trace is missing but I was able to check another board and there is continuity there. So what the heck would "bypass" mean? I am going to ignore the via as it seems irrelevant. I am going to run a wire from C149 to that pin and see what happens. I also know that I did not give enough cleaning time for that U30 chip. I am really soaking the board in ISO for a couple of days. see if that helps. Otherwise I may need to lift the chip. Thanks for the feedback.
 

djc6

New Tinkerer
Oct 19, 2024
38
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8
I watched a great video on this topic earlier today. The focus is on missing pads for capacitors locations on Mac logic boards:

 
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