Hi. I need some help troubleshooting the issue (which is a bit odd to my limited experience) with the A2338 Macbook.
Initial symptoms:
One day the laptop refused to wake up (as it seemed at first), spinning the fan on full blast, with no picture on the screen.
Force rebooting didn't help. To check if it boots at all I connected the external display and surprisingly it booted to the system, and I was able to log in to the system.
However, I noticed that it was in some weird state:
Software restore attempts:
Suspecting software-related issues, I managed to boot into recovery (again, only with an external screen) and back up the (encrypted) data via the "Share Disk" feature.
Attempts to run diagnostics failed with the message that the laptop has to be connected to the internet (but it never showed any WiFi network selection screen, I assume due to WiFi not being detected, as with the live system.)
Next, I attempted to revive/restore the laptop via DFU mode and the working host Macbook. Even though the laptop was recognized by Apple Configurator to be in DFU mode, both revive/restore failed with the following error message on the installation step.
The System cannot be restored on this device.
Gave up waiting for the device to transition from DFU state to DFU state.
[com.apple.MobileDevice.MobileRestore - OXFCA (4042)]
Hardware inspection:
After disassembling the laptop and inspecting the motherboard I did not find any signs of liquid damage, corrosion, or any visually damaged components.
Observations:
I used this resource as an initial guide on what to check.
PPBUS_AON:
without the battery - 12.3V, dropping down to around 9V (hard to tell exactly due multimeter sampling rate) once a second.
with the battery and DC in - 11.78V, stable, slowly increasing by millivolts, 11.62 without DC in
PP3v8_AON: 3.8, but "boot looping" is similar to PPBUS_AON to lower value.
PPDCIN_AON_GHGR_R: 5.15V
Current sensing resistors around ISL9240: R5221, R5222, R5261, R5262 are around 1.00 Ω
As I understand, ISL9240 may be the problem. But want to gather a bit more information before making any conclusions.
Would appreciate any help.
Initial symptoms:
One day the laptop refused to wake up (as it seemed at first), spinning the fan on full blast, with no picture on the screen.
Force rebooting didn't help. To check if it boots at all I connected the external display and surprisingly it booted to the system, and I was able to log in to the system.
However, I noticed that it was in some weird state:
- The fan was still blasting at full speed. It's blasting even when the system is off, but when you open the lid or connect to the charger. Closing the lid (with the system off) turns off the fan.
- Even though the screen was not working, it was recognized by the system.
- Wifi or Bluetooth were not detected.
- Battery showed 1%, but checking system info about the battery (no serial number or other battery info).
- The system will work for some time, but reboot after some time with the purple "death" screen.
Software restore attempts:
Suspecting software-related issues, I managed to boot into recovery (again, only with an external screen) and back up the (encrypted) data via the "Share Disk" feature.
Attempts to run diagnostics failed with the message that the laptop has to be connected to the internet (but it never showed any WiFi network selection screen, I assume due to WiFi not being detected, as with the live system.)
Next, I attempted to revive/restore the laptop via DFU mode and the working host Macbook. Even though the laptop was recognized by Apple Configurator to be in DFU mode, both revive/restore failed with the following error message on the installation step.
The System cannot be restored on this device.
Gave up waiting for the device to transition from DFU state to DFU state.
[com.apple.MobileDevice.MobileRestore - OXFCA (4042)]
Hardware inspection:
After disassembling the laptop and inspecting the motherboard I did not find any signs of liquid damage, corrosion, or any visually damaged components.
Observations:
I used this resource as an initial guide on what to check.
PPBUS_AON:
without the battery - 12.3V, dropping down to around 9V (hard to tell exactly due multimeter sampling rate) once a second.
with the battery and DC in - 11.78V, stable, slowly increasing by millivolts, 11.62 without DC in
PP3v8_AON: 3.8, but "boot looping" is similar to PPBUS_AON to lower value.
PPDCIN_AON_GHGR_R: 5.15V
Current sensing resistors around ISL9240: R5221, R5222, R5261, R5262 are around 1.00 Ω
As I understand, ISL9240 may be the problem. But want to gather a bit more information before making any conclusions.
Would appreciate any help.
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