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Not Charging but works from battery H20 damage Macbook air

brooke.j

brooke.j

Member
Hi,

I have a Macbook Air 820-3437-A. No Green light. After cleaning up some corroded caps around U7100 it will boot from the battery and work fine. It will not boot or charge. Do I have bad I/O board?
Coming off the DC board I have 3.14v but when I connect it to the MB at J7000 I get a fluctuating voltage from 4v to 8v on pin 1. Should I have more voltage coming from the I/O board. I've tested every capacitor on the PPBUS_G3H for short but can't find one.
 
brooke.j

brooke.j

Member
The green light actually blinks every now and then. So I've searched all over and I can't find out what voltage I'm supposed to get from the I/O board.
 
brooke.j

brooke.j

Member
I've been doing some reading on the forum. Should pin 3 of MLB to LIO Power Cable Connector (PP5V_S4RS3) have 5v already? Or is that created after it boots? I know I watched a video of Louis' that explained this. Damn memory.
 
brooke.j

brooke.j

Member
PP3V42_G3H is at 0.12v so I really need to get that going first of course. Just looking for direction if computer boots and works off battery but not charger and is not charging.
 
brooke.j

brooke.j

Member
From another post i see that I needed to test U6901 on the DC IN board itself.

U6091 Pin 5 (PP3V42_G3H) = 0.04v
U6091 Pin 1/2 (SMC_BC_ACOK) = .5v

Voltages at J9500

SMC_BC_ACOK = 0v

PP3v42_G3H = 0.028v

SYS_ONEWIRE = .46v

DC board has pins 1/2 at 3.2v

So I know I need to get PP3v42 back to the DC board or get that working first. The low voltage means a short somewhere but just on the PP3V42? I'll look at every cap and resistor on that line then or should I be focused on something else?
 
brooke.j

brooke.j

Member
Ok now once I put the I/O cable on I get an orange light. I'm going to put it all back and see if it will boot and charge.
 
brooke.j

brooke.j

Member
What I'd like to figure out is why that resistor created that situation and how I would have found it or even known to look for that. Looks like it was on CHGR_SGATE_DIV and PPDCIN_G3H_INRUSH
. Well all I can say is that I was having an issue with PPBUS_G3H and that the computer would work on battery and not Charger so looks like I'll be looking into those two things above. If anyone has some info to share please do.
 
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