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[SOLVED]820-2838 Won't turn on from Keyboard.

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gcain

gcain

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Works fine if I short the pads.
Tried new top case, keyboard, trackpad, cables. I get no response from the power button, yet all other keys work fine.

SMC_LID is High and Low when the lid is up and down.
Pin 3 on J5700 shows 3.42 but doesn't react when I press the button.

Similarly, U5010::7 doesn't react and is always 3.4

Initially I figured it was the keyboard since there is no response at all.

Any suggestions on what to look at next?
 
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arghhh

New member
Pin 3 is ground. There is no way it shows 3.42v. I'm going to disregard that as a typo.

This is likely going to be a broken trace. Check the resistance from the trackpad to U5010 along SMC ONOFF L.
 
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arghhh

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Only thing this can be is a corroded connector, otherwise the board is fine and it is a parts issue.
 
gcain

gcain

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Everything looks really clean.
Jacks look good.

I can read the 3.4 all the way to the jack on the Trackpad.
 
D

dukefawks

Administrator
This is not rocket science. Pinout for the air keyboards is the same as all MacBooks. I think pin 5 is power button. Check if there is 3V on the connector and see if it powers on if you short that pin to GND.
 
gcain

gcain

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dukefawks said:
This is not rocket science.
Click to expand...

Yeh, I realise this is layer 1, that's why it has me confused.

dukefawks said:
Pinout for the air keyboards is the same as all MacBooks. I think pin 5 is power button.
Click to expand...

Pin 11, I think.

dukefawks said:
Check if there is 3V on the connector and see if it powers on if you short that pin to GND.
Click to expand...

The pin has 3v on both the jack on the LB and TP.

If I short the pin on the jack, it boots. Press the power key, no boot.

Tried with a new keyboard...
 
gcain

gcain

New member
KBD Connector on the Trackpad?

Pin 5 on KBD jack on the track pad reads 3v and doesn't go down on btn press.
 
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dukefawks

Administrator
Bad keyboard or trackpad then.
Well there is one very unlikely option. Measure resistance from pin 5 to 3V42 bus, should be about 10K.
 
gcain

gcain

New member
I'm getting about 70k from pin 5 to the power pad.

Just swapped out to a new Trackpad too.


This thing is sending me loopy.
 
D

dukefawks

Administrator
Are you counting from the correct side pin 5? Pin 5 should have 1K resistance to the power on pads on the board and 11K to 3V42 rail. There is a 1K resistor in line with the power button on the trackpad.
 
gcain

gcain

New member
Hopefully I had it wrong.

Do you mean the jack on the Trackpad that the keyboard goes into?
 
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dukefawks

Administrator
I don't see how keyboard connector on the trackpad can be interpreted any other way. Also mentioning that all macbook keyboards have the exact same pinout and exact same 30 pin connector.
 
gcain

gcain

New member
Yeh, not sure either. But considering there was case for possible confusion, it seemed worthwhile confirming.
 
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dukefawks

Administrator
So did you measure again on pin 5? 11K to 3V42 and voltage with and without power button pressed. Also resistance from pin 5 to the pads on the board.
 
gcain

gcain

New member
Been out the office today.
Will take another look when I get back in on Tuesday.

Thanks for following up.
 
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