MacAir 820-3209 not turning on

arnonabuurs

New member
Hi Guys, I have a Mac Air 13" 820-3209 which has a green light, orange light, and a spinning fan, but no chime, not turning on. I have checked all main power rails from 8.6V to 1.05V and they all seem to be present, even the S0 versions. Any tips on what to check next. issue might be in some data line? I fixed quite a number of boards (thanks Louis!) but all of the had power or backlight issues. This one is making me sweat:). Any tips welcome.
 

arnonabuurs

New member
Hi Guys, it seems I forgot to check Vcore as indeed something is fishy there, some of the voltages are not correct as you can see in attachement. R7402 is not corroded. The board has no signs of liquid damage, it looks pristine under the microscope. I will check some of Lewis VCore videos and see if I can trouble shoot the issue.

Edit: R7402 = 91.3K ohm
 

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arnonabuurs

New member
So as for R7402, pin 2 has 8.4v but pin 1 340mV. I have just replaced it, before it showed reading pin 2 = 8.4V and pin 1 180mV. Another thing to mention is the CPU gets quite hot so it does get some power.
 
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dukefawks

Administrator
Vcore is there! AXG will only come on after successful detection of the LCD. If this is not corrosion this can really be anything. 3208 and 3209 boards do have issues with the PCH. Press on it and power on or give it some heat (150C) and try again.
 

arnonabuurs

New member
Just got another Mac exactly the same issue, no signs of liquid, R7402 is 90ohm and looks in good condition, the reading of PPVCORE_S0_CPU_REG = 0.8v which seems not enough. Should I spend time on it or these are just difficult to fix and I better fix another one instead?
 

dukefawks

Administrator
Zelfde ellende denk ik. Eigenlijk zou ik er wel even naar willen kijken als je ze op zou willen sturen. Is nu toch wel een issue aan het worden met 3208 en 3209 borden.
 

arnonabuurs

New member
Ik zit in Thailand dus denk niet echt dat het de moeite is. Ik kan ze wllicht inruilen met de klant voor replacements en ze dan opsparen tot ik er een aantal heb en meenemen als ik naar NL kom of een aantal tegelijk opsturen.
 
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