820-01041 wake up problem

[bartech]

after battery change after some time there was short on J6951 and after that when you close laptop and opel lcd dont wake up, mac work there is sound and touchbar is woking.
i change j4800 and j4801 but still the same.

 

[2informaticos]

Check U4802 signals, with lid open/closed.
Use magnets to simulate the lid position...

 

[bartech]

when i get magnet volts go to 0v left and right work like that

 

[2informaticos]

IPD_LID_OPEN signal also reacts correctly?

 

[bartech]

yes but sometimes nedd some time to change to 0v, one time i use only one magnet and go to 0v on left and right

 

[2informaticos]

If machine has sound and working touchbar, it wakes up.
You may have problems only with image, or backlight.

 

[bartech]

still same, i check and found that you cant change brightness i try to change on touchbar but nothing change stay as same brightness.
When it put screen to sleep and switch off i can wake it up by power button and it wake up the screen

 

[bartech]

now no backlight i change u8400 and nothing change

 

[bartech]

on external monitor there is video

 

[2informaticos]

Do you still have image on internal LCD?
Did you test with good screen?

 

[bartech]

check on other working lcd the same , no backlight.

 

[bartech]

u8400
1,2 - 0v
4-0v
5-5,5v
9-0v
10-0v
11-15,7v
12-0v
15-5,5v
16-5,5v
17-0v
18-5,5v
19-0,13v
21-0v
22-0v

 

[2informaticos]

Still not clear if missing only backlight, or image too.

"9-0v
10-0v"
F8400 burnt?
Check diode mode to ground at R8400.

 

[bartech]

missing only backlight
sorry check again when for sure there is data
problem was that there is apple logo and than black screen when i check

1,2 - 0v
4-0v
5-7,38v
9,10 - 17,10v going up slowely stop at 18,90
11- 9,47
12-0v
15-7,23v not stable
16-7,23v not stable
17-5,10v
18-7,80v
19-0,27
21-42v
22-0v

 

[2informaticos]

Change your multimeter battery and post again voltages...