820-000165 no power

So this was originally water damaged macbook air. changed u7100 and put it though ultrasonic cleaner. afterward computer was working fine, and passed asd. It sat in my shop for 89 days (i only hold them for 90). Went to show customer and now does power up.


Orarge light
no fan spin
pp3v42 - 3.42
ppbus - 8.58
pp3v3_s0 - 0
pp3v3_s5 - 0

what line is the the vcore?
 

JohnB8812

New member
If you don’t have S5 rails you won’t have VCore. What is the resistance to ground on 3v3_S5? Is PPVRTC_G3H present?
 

JohnB8812

New member
If you mean 2.82 volts then that would at least indicate a problem around U1900 and the clock circuit as it needs to be 3.3. Also yes as Louis asked is G2 EN present?
 
okay replaced u1900 now have 3.322v
SMC_PM_G2_EN - 3.420v

Edit: have fan spin now (its on max) but no chime.

I'm not sure if this is vcore but

PPVCC_S0_CPU_PH1 - is 1.808

I have no light on usb mouse.
 
Last edited:

dukefawks

Administrator
Check termination resistors and traces from U6100 to CPU and SMC. Also suspect would be crap under the SMC. It all depends on where the original corrosion damage was.
 
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