820-00281 Only turns on from charger

Greg

New member
Have a strange one here. Will only turn on from the charger does not respond to opening the lid or power button. But there are other issues too when it does boot it will load into the critical update, Can only get into operating system in safe mode, had mild liquid damage around U3900 from what i am reading the critical update is usually from u3900 failing. but the not turning on from the power button or opening the lid is confusing. Power button does work with SMC reset. But thats it even when the macbook is on the power button wont switch it off. If you close the lid in safe mode and open it again the screen wont wake im not sure if this is normal in safe mode or not.
I just cleaned up the mild liquid damage. no idea where to start.
 
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Greg

New member
Should ad that it does charge the battery and will run off the battery when disconnect charger. No liquid damage on the power button or the connector. Only way to turn it on is plugging in the charger and do a SMC reset. Or plug in charger with battery disconnected.
 

2informaticos

Administrator
Staff member
Monitor SMC_ONOFF_L level.
Disconnect J4900 if needed.

Critical update error is related with the f**g touchbar.
Check SMC_LID signal, disconnecting completely the touchbar, J4401/02.
 

No-Clean

Member
I was going to post this same exact issue, since this one was left unsolved what a better place to start than here, mine is a clean board no liquid damage, also no critical update required on this one, closing the lid does nothing.

When power button is pressed SMC_ONOFF_L drops to 0v but does nothing, I have also tried with button disconnected and shorting SMC_ONOFF_L to ground does nothing.

Thinking it could be either the SMC and or U5226 I replaced both in a desperate attempt, but no luck.

Maybe @2informaticos has new intel on this issue.
 

No-Clean

Member
When the computer is ON and PM_PWRBTN_L is 3v and it is shorted to ground for a force shutdown say holding it down for more than 6 seconds nothing happens either. Will this have to do with PCH?
 

2informaticos

Administrator
Staff member
"When the computer is ON and PM_PWRBTN_L is 3v and it is shorted to ground for a force shutdown"
Shorting PM_PWRBTN_L to ground, why???
 

No-Clean

Member
I meant shorting SMC_ONOFF_L to ground simulating a forced shutdown to see if the power button action works
 

2informaticos

Administrator
Staff member
Should be PCH issue.
Be sure all its RTC signals have stable and correct level.

Do you still have 1V at PM_PWRBTN_L in off mode?
 
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