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820-02020 Backlight very dim and after 10 sec no image

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Bravo2001

Member
Hi,

I have a 820-02020 with liquid damage around backlight area. Was working fine only thing was no camera. So tought lets ultrasonic to clean. And now I have a very dim image (apple logo) and then after 5 sec no image. Also after 30 sec, lcd comes on for 2 sec with backlight and image (login screen) but goes away. Thought maybe backlight issue orso but this is steady 43V until image dissapears. Figured out that everything goes black after LCD_PWR_EN goes to 0v.

Why does LCD_PWR_EN go to 0v??

Please advise.
 
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Bravo2001

Member
Tested, with known good compatible screen. Same result...

Checked LPDP_INT_HPD, goes to 1,1v for 10 sec. then goes low at the same time image disappears. Also no backlight on screen but backlight voltage is 43v until LPDP_INT_HDP goes low.
 
2informaticos

2informaticos

Administrator
Staff member
1.1V looks too low; compare with good M1 board.
You can't expect backlight, one image is gone.
But 43V looks good, there should be backlight in the first 10s.

Just in case, see if DFU helps in this case.
Save data before doing DFU Restore.
 
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Bravo2001

Member
1.1v is correct, checked on working M1 Board.

There is also an issue with keyboard, trackpad and external USB keyboard. When I connect on external monitor boots up to login screen but can't use mouse or keyboard. Als connected external USB keyboard, nothing...

Looks like more problems, What could I check more?
 
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Bravo2001

Member
Can't get it in DFU mode?! Maybe something to do with USB-C connector (as the external keyboard also doesn't work)

What I noticed, after image goes away. It still boots. When I press power button, the screen comes up with backlight etc... but after 5 sec goes away. And comes back again when I press power. Also when I firs connect power you hear chime, if I press power I have an Apple logo with backlight. Goes away after 5 sec!

Ps. This only works when power is connected not on batt?!?

Could it have something to do with open lid sensor? Maybe the MacBook thinks the lid is closed.

Haha, after writing this down, I thought let me have look wat voltage open lid was giving. JR200 AMR_LEFT_OR_ND_1V8 was zero... But more concerning, PP1V8_AON was zero... I guess that one is needed!

Keep you posted
 
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