Re: A2289 No PPBUS_G3H
No Voltage at C1027 when injecting 1Volt at F7000 PPBUS_G3H
No Voltage at C1027 when injecting 1Volt at F7000 PPBUS_G3H
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MEOWING IN THE IMPOSSIBLE UNIVERSE! -
Re: A2289 No PPBUS_G3H
To me, it appears to be safe to inject a higher voltage to see if someone heats up. Consider increasing the voltage slightly. To rephrase, the CPU high side mosfet does not appear to be leaking. If it was, then the CPU is probably already dead.
Injection would be much like 'beating a dead CPU'.Comment
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Re: A2289 No PPBUS_G3H
Should I increase it to 2volts. I know 5Volts will fry the CPU for sure. a sweetspot would help to inject more voltage I would hate to fry the CPU at this point. I know I am so close to repairing this but its just a simple short somewhere that needs to be found.sigpic
MEOWING IN THE IMPOSSIBLE UNIVERSE!Comment
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Re: A2289 No PPBUS_G3H
Always use current limit on your psu - first start with lover current and gradualy rise up. Observe voltage drop on psu and calculate output power - when you rich about 1w or so, you can spot thermal difference, and no point to go higher.
Alcohol is not good in this type low power scenario, because you can not spread it evenly thichness, and with evaporation he cooled board significaly, masking your short.Comment
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Re: A2289 No PPBUS_G3H
After further investigation with lighter voltage the CPU is increasing in heat. I am assuming this is the culprit
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MEOWING IN THE IMPOSSIBLE UNIVERSE!Comment
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Hi everyone. Just a reminder I am not a professional repair technician, fixing Apple electronics is my hobby.
Recently got my hands on MacBook Pro A2289 with interesting behavior. Pristine condition, no water damage, no visual issues whatsoever. It has no image, no CapsLock, no life except the fan is spinning. But it is able to boot into DFU and recognized by another MacBook. I tried to revive and restore the laptop, but the process ends when the MacBook usually should show an Apple logo with a progress bar. I assume the main power lines and T2 are working. It seems like the Intel... -
Hello to all ! I follow you but this is first time write !!
your forum is the best !!
so I’ve a2289 with water damage ! In first time other friend have clean and work ! But after some time stop working !
now, I open the MacBook and I see a lot of corrosion near backlight circuit (I attach some photos about that ) I think the problem is on backlight maybe bcs do strange boot then reboot (attach video ) I change some thing on the circuit like :
q8400
q8401
D8410
and the resistor R8431
if I check PPVIN SOSW LCDBKLT_R I’ve 12,9v
on...04-03-2025, 06:45 PM -
hi guys I have a 2020 MacBook Pro A2289 it has the i5 CPU and is now acting as if its dead,
when I plug in the charger cable with a volt meter thing connected as well its drawing 20.3v and 1.11A
if I press the power button nothing happens.
but if I hold the power button for 7 seconds or more the voltmeter drops all the amps down to 0.00A but voltage stays the same.
any ideas where I can check ??
from what I can gather it must be charging the battery at 1.11A as nothing happens when the power button is pressed. I can successfully... -
Hi everybody,
I have Macbook A2289 820-01987A.
It have had 1.8V short circuit problem that I fixed.
But after 20 minutes working the backlight went out.
I found out missing of EDP_BKLT_EN going to U8400 from U0500.
Ground down level goes from U0500. (I tread to remove R8442).
The machine starts perfect. I can watch image on the screen with a flashlight, and it works with the external screen.
Do you have any suggestions what kind of problem I came across?
Thank you in advance.... -
As always with nearly every T2 board, board is squeaky clean.. 3v3_G3H_RTC had a short..
Of course in TPS chip.. I replaced it..
Found another short in 3v3_G3H_RTC in SoC PMU; replaced..
Board was taking 5v 0.40a on one port and another port is erratic.. ammeter turns on and off.. In thermal camera found TBT ROM was getting warm up to 38c.. PP3V3_UPC_XB_LDO had low diode mode reading..
Replaced TBT ROM from another known-good A2289..
Now board switches to 20v and consumes low wattage.. gets into DFU revives and restores successfully without errors.....
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