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Macbook Air - 820-3437

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vaswaniraj

New member
Hi Louis, Duke, and group,

Yesterday I received a Macbook Air - 820-3437. Only closely looking at the logic board I do not see any liquid damage to the board. When I plug in the charger I can see the light comes one with Green and then turns amber. The fan as usual spins, stops, spins, stops and then continues to spin. Can you advice me where to look for in order to troubleshoot the board. I was watching a video of Louis, where it mentions about the backlight. My understanding is that when it is a backlight problem, we can see the Apple logo but DARK, Am I correct ? If it is not the backlight then please advice further steps to troubleshoot this board. Thanks in Advance. Raj.
 
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aprendiz

Moderator
Does it chimes?? Capslock works?? PRAM reset?? Use a flashlight on the back of the display in the apple logo and check if there is any image....
 
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vaswaniraj

New member
Hi Aprendiz

Chime - No chime
Caps lock - Doesn't work
Use a flashlight - I did put the flash light on the back and there is no image.

Raj.
 
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vaswaniraj

New member
There is no water damage on any part of the board. I checked J6100 and U6100 and nearby area, no traces of water. U1950 also cannot be seen with any water damage.
 
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dukefawks

Administrator
If it does the 3 times on/off it is sort of working. Disconnect IO flat cable and trackpad. See if USB mouse lights up after the 3 on/off cycles.
 
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vaswaniraj

New member
Hi Duke,
I disconnected the IO Cable ( the IO cable is the cable that is a Flat ribbon, that runs on the top of the fan ) correct me if i am wrong. I did not connect the trackpad cable. Connected the USB mouse but there is no light on the USB Mouse. Also the fan does not spin 3 times, it only spins for 1 time then stops and then for the 2nd time continues to spin continuously.
 
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vaswaniraj

New member
Hi Duke,
I checked the R6110 and its traces. The traces of Pin 2 of R6110 end up at 3 points - R6120 (Pin 1) , R6125 ( Pin 2 ) and on Probe point TP[1] SPI_CS0_L. They all beep in continuity mode of the MM.
 
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dukefawks

Administrator
Do I really need to explain you need to test ALL resistors r6110 to R6133. That are a lot of resistors and traces.
 
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vaswaniraj

New member
Hi Duke, As i progressed in checking the traces, I noticed that the continuity between R6111 ( Pin 1 - SPI_CLK_R ) to R6113 ( Pin 2 - SPI_MISO_R ) is missing. If i run a jumper wire to maintain the continuity of the traces, would that help. Or I have to change the resistor. Please advice. Raj.
 
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