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A2779 - 820-02841 - No image - U6070 troubleshooting
- Thread starter joesklar
- Start date
Low/short reading gave a chance for bad C5701.
Your reading points directly to bad U5700.
Your reading points directly to bad U5700.
Happy New Year!
You were right, U5700 was bad. Replaced and now I have the following status:
Boot looping every 15 seconds. Image is present, but no backlight.
I will look to troubleshoot the backlight circuit.
Any ideas on the boot looping, maybe related to backlight?
Thanks
You were right, U5700 was bad. Replaced and now I have the following status:
Boot looping every 15 seconds. Image is present, but no backlight.
I will look to troubleshoot the backlight circuit.
Any ideas on the boot looping, maybe related to backlight?
Thanks
Many times, boot looping is solved by DFU restore.
Be aware, that will erase SSD.
You can try with revive instead.
Be aware, that will erase SSD.
You can try with revive instead.
Thanks for the info.
I haven't attempted a DFU mode restore before. I just installed Apple Configurator on a host A2485. I have the Thunderbolt cable in the uppermost USB-C slot closest to the MagSafe connector for both host and target.
I can't get the A2779 into DFU mode. It just continues to boot loop. Do you have any advise for what to attempt? Key sequences etc. The videos I found online seem to have conflicting information..
I haven't attempted a DFU mode restore before. I just installed Apple Configurator on a host A2485. I have the Thunderbolt cable in the uppermost USB-C slot closest to the MagSafe connector for both host and target.
I can't get the A2779 into DFU mode. It just continues to boot loop. Do you have any advise for what to attempt? Key sequences etc. The videos I found online seem to have conflicting information..
Thunderbolt cable is not the best option; try normal cable.
You can also try DFU blaster.
You can also try DFU blaster.
Thanks, DFU blaster worked great for getting it seen by Configurator. I'll use that again for sure.
It gets to the last step of the restore, at which point it reboots and then says "unable to complete restore" or something along those lines.
The boot looping is not happening any more.
Now, the chime happens, Apple logo appears for a split second and then it is just stuck on a blank screen.
20V up to 500mA as the Apple logo appears, and shortly after is just stuck at around 150-160mA - inactive but on.
No video output to external monitor.
It gets to the last step of the restore, at which point it reboots and then says "unable to complete restore" or something along those lines.
The boot looping is not happening any more.
Now, the chime happens, Apple logo appears for a split second and then it is just stuck on a blank screen.
20V up to 500mA as the Apple logo appears, and shortly after is just stuck at around 150-160mA - inactive but on.
No video output to external monitor.
Did you try restore, or revive?
When it gets stuck in blank screen, Caps Lock reacts?
Try again DFU with LCD assembly disconnected.
Keep the battery and trackpad connected.
Keep the battery and trackpad connected.
Okay so it appears as if the problem may be the display assembly...
DFU restore still did not work with the LCD disconnected, however I was able to boot with an external monitor connected. I've since found the device is activation locked! Now I will have to contact the eBay seller as they said there was no activation lock...
Is it possible that the DFU restore didn't progress due to activation lock?
The results are repeatable now:
Screen connected, the device is stuck in boot loop. No keyboard backlight, no caps lock LED.
Screen disconnected, the device boots as expected.
DFU restore still did not work with the LCD disconnected, however I was able to boot with an external monitor connected. I've since found the device is activation locked! Now I will have to contact the eBay seller as they said there was no activation lock...
Is it possible that the DFU restore didn't progress due to activation lock?
The results are repeatable now:
Screen connected, the device is stuck in boot loop. No keyboard backlight, no caps lock LED.
Screen disconnected, the device boots as expected.
DFU should complete even with activation lock enabled.
Forget about DFU, if now boots.
Forget about DFU, if now boots.