A1708 820-00840-A Needs SMC reset to start macbook after lid_close

2informaticos

Administrator
Staff member
"You can check its reaction aproaching a magnet; pin 25 should drop to 0V."
Of course, this doesn't help if you don't get first 3V on the signal; in normal mode, lid open.

Remove R5257 and check voltage on its pad 1 (going to pin 25 of J6600).
In this way you can see if problem comes from audio flex, or MLB.
 

jhk753

New member
So indeed I never get 3Volt on pin 25 as far as I can measure… so I haven’t tried the magnet indeed…
For now based on what’s happening with the brand new audio flex I’m thinking there is a problem with MLB I’ll retry a second ultrasonic bath and if nothing happens I’ll bring it to someone with proper micro (de)soldering experience. I don’t have the equipment to do that properly.

by the way the fluid you recommend to do ultrasonic bath is not available in France. Do you know of any good alternative? I was going to go for 100% isopropanol in the bath.
 

2informaticos

Administrator
Staff member
Don't waste the time with ultrasonic cleaner now; you can generate more damage.
You must diagnose first where the problem is; MLB, or audio flex/connector.

If you was able to get acces on old hall sensor (removing the silicon), check continuity from its pins to corresponding MLB points.
 

jhk753

New member
Ok any tips to scratch the silicon without breaking everything? Should I try to heat it with a hairdryer or something?
 

2informaticos

Administrator
Staff member
If you can't detect corrosion there, better don't touch it.
Inspect J6600 solders and contacts.

"Remove R5257 and check voltage on its pad 1 (going to pin 25 of J6600)."
Find someone who can do this for you.
Check with audio flex connected, of course.
 
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