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Macbook Pro A2159 820-01598

Instafixx

Instafixx

Active member
Machine switches on.
Question Mark Folder.
Command + R leads to internet recovery but No Wifi Networks Showing.
The Globe spins with Choose network option that wont show any wifi

Board is clean.
Little Green around U7100 . Cleaned it. All points have proper diode mode readings.
 
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Instafixx

Instafixx

Active member
I connected a External LAN Cable and Tried Flashing from a USB.
Succefully went into recovery.
SSD is visible as "Uniniated" ( The customer himself had tried doing recovery)
Wifi is also working in this menu.

I tried Re-Installing the os but the startup security wants me to press command+r and then do it.
And when doing Command + r i am unable to move forward because of the spinning globe with no wifi.

Did a succesful DFU Restore. Still the same.

Also did a NVRAM Reset.
 
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Instafixx

Instafixx

Active member
my bootable installer is High Sierra.
Since this was launched with Catalina - can that be a reason its going to Internet Recovery?

Also its Flashing a Question Mark folder. It will not go into Safe Mode.
 
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Instafixx

Instafixx

Active member
I tried thunderbolt Bridging as well to supply internet access. Didnt Work

I connected this Mac via Target Disc Mode and Restored the Image of My Mac to this.
Now i get the error "Your Computer Restarted because of a problem" Then stuck at a blank screen with Backlight on.

Command + R - Stuck on Apple Logo.
Bootable USB - Select Between Macintosh HD and MacOS - then stuck on Apple Logo.

The Machine definitely has a hardware issue.
Requesting assistance
 
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Instafixx

Instafixx

Active member
Tried Safe Mode. Stuck in Apple Logo.
Apple has stopped making thunderbolt to Ethernet adapters.
Any third party brand adapter that is known to work in system recovery ?
 
Instafixx

Instafixx

Active member
With Board on Desk. The Ampere settles at .250A.

Checked the board.
PP0v95_S0_CPUVCCIO_REG_R is Present
PVCCIO_EN signal at R8165 is Present
PPVCCEDRAMS0_EN_FILT_BUF signal at R7766 is Missing
Diode Mode to Ground is .543.

Resistance Across Pins at R7766 is 40k Ohms.
 
2informaticos

2informaticos

Administrator
Staff member
I think EDRAM voltage is not present so early as normal.
You should confirm with good board.

Just in case, check what happens installing Windows, or Linux.
 
Instafixx

Instafixx

Active member
I do not have another board but as per the article at Repair.Wiki EDRAM voltage should be present. Any wild guess ?

It has some hardware issue for sure.
Tried installing windows from a bootable USB.
Machine again stuck at Apple Logo.

Thermal Camera shows U2800 getting hot - Have removed the shield.
 
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Instafixx

Instafixx

Active member
Replacement Done.
This one heats up too.

Same Issue

Will this work without that chip.

Without U2800. Y3000 gets mildly warm. Goes upto 37 Degree Celcius.
 
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2informaticos

2informaticos

Administrator
Staff member
You will lose USB communication once macOS starts loading.
But you can try without U2800; should boot at least.
 
Instafixx

Instafixx

Active member
I tried without U2800.
Its the same situation. Booting with the same error.

I guess will have to return.
 
Instafixx

Instafixx

Active member
I just saw it once when somehow by ethernet i entered the Recovery OS.
I formatted the Disk via Disk Utility and connected the wifi too.
The re-install process got interrupted and it rebooted.

After that i was never able to enter the Recovery OS even with ethernet.
 
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