Macbook A1990 820-01041 Sensor Issue

[Instafixx]

Device had a flexgate issue. Fixed that. But facing a weird issue now. When device goes to sleep (Whether by putting the LID down or after the time has passed or by manacling putting it to sleep. The Display will not turn back on - the device wakes up though.

the board is free of any greenery.

 

[Instafixx]

Now machine will not boot. Taking 20V at very little AMP Draw.

DFU Restore. Machine is on now. But same issue.

The device has a weird issue. It won't stay on if it's not on charge. Once removed from charger it goes off and won't turn back on - (with and without battery).

To switch this machine on,
Need to connect it to a Host Mac via Master Port. and it turns on(Have to plug in the charger)
This is very new and weird to me.

 

[2informaticos]

Check both lid sensors signals.

 

[Instafixx]

LID_OPEN_LEFT/RIGHT both are 1.8V with bare board on bench.

 

[2informaticos]

Do you get correct CPU core voltage behavior then (board alone)?

You should check lid signals when the problem appears.

 

[Instafixx]

are you sure its a Sensor issue ??

 

[Instafixx]

Have solved all other issues . Some dirt at the battery connector screw. Sleep/Wake Issue prevails.
Let's not use the LID. I select the sleep option from the menu and put the device to sleep. Then if I try and wake it up it wakes up in a no backlight scenario .

LID angle sensor issue or backlight circuit issue ??

 

[Instafixx]

Using a 96W charger - the device will not turn on without a battery connected. How do I check sensor signals ?

Once device goes to sleep. it will not boost the backlight circuit once it wakes up.

 

[2informaticos]

Missing one lid sensor signal, can cause weird issues...

 

[Instafixx]

Checking with Board and Battery on Bench and display connected.

LID_OPEN_RIGHT/LEFT is 1.8V.
PPVOUT_S0_LCDBKLT is 50V.

Approach either sensor with magnet and the corresponding line goes to 0V - screen stays on.
Approach both sensors with Magnets - the lines go down to 0 and screen sleeps.
Remove magnet.Both lines are 1.8V. No backlight on screen.
PPVOUT_S0_LCDBKLT is 55V.

At this point have to shut down and restart the Mac every time to get backlight.

 

[2informaticos]

Try again DFU restore...

 

[Instafixx]

I did dfu restore again this morning.

 

[Instafixx]

So it is in a LCD EEPROM issue. I brushed a chinese EEPROM dump for a non genuine part. I get lines on my display but the issue is resolved. I Brush back the original dump of this screen - lines gone and light issue is back.

I need EEPROM file from a working a1990 screen to solve the issue. Any help regarding that ?

 

[Instafixx]

Found a EEPROM. Issue Resolved.

 

[2informaticos]

Thanks for sharing.