820-2850 Restart when shutdown in OSX

Don Anton

New member
Hi,
This is a clean board. No liquid damaged. It can turn off by pressing power button. How ever when it shutsdown from osx restarts.

SMC_ONOFF_L is 3.3and when shutdown goes to 0v and back 3.3 as usual.

Any idea?
 

2informaticos

Administrator
Staff member
Did you try PRAM reset?

Also try known good USB OSX, disocnnecting internal HDD/SSD.
Don't forget to test without battery too.
 

Don Anton

New member
Hi I tried with kown good USB OSX and did pram reset. Tried different rams one ram slot at a time battery disconnected. Still restart when shutdown from osx but can shutdown pressing the power button.
 

Don Anton

New member
I notice one thing to shutdown from the power button need to hold for 5 second to turn off. if i press the power button for 2,3 seconds it restarts.
 

Don Anton

New member
Also tried with different macbook, and L?B out of the body connecting external monitor usb mouse and usb osx. still same
 

Don Anton

New member
HI Info, This is SOLVED. I noticeed PCIE_WAKE_L was going down to 1.9v after couple of seconds. check resisters all good. Replaced U3900 SOLVED. Thank you very mcuh for your help. See you until nest time I trouble you.:D
 
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