Without the screen, it boots up and works fine, but with the screen installed, the iPad will not boot. Through testing, i have determined that the problem occurs when the screen cable is attached to the 2 o'clock connector.
I checked the components connected to the FPC with a multimeter and found that the PP1V8_S3 rail is not a complete short circuit, but the resistance is unusually low, around 100 ohms. It looks like a half-short. I did not checked a short in any of the other components connected to the PP1V8_S3 rail.
The screen or the fpc connector is not the cause. If you install this screen on another iPad, the screen works fine. And I already replaced the fpc connector once, but the symptoms did not change, and the diode values on the other connector pins are all fine except for the pins connected to PP1V8_S3.
Anyway, when I remove the screen, it boots up normally again, and I also measure 1.8v on the PP1V8_S3 rail. However, when I reinstall the screen, it starts the boot loop again.
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I injected current into the PP1V8_S3 rail through a DC power supply, and to my surprise, one of the RAMs on the A12Z AP is generating heat. I didn't checked any heat on the other PP1V8_S3 components.
+
I injected current into the PP1V8_S3 rail through a DC power supply, and to my surprise, one of the RAMs on the A12Z AP is generating heat. (Only one of the two ram modules generates heat.) I didn't find any heat on the other PP1V8_S3 components.
Could this be a problem with the RAM? If the RAM is the problem, it seems impossible to repair.
Without the screen, it boots up and works fine, but with the screen installed, the iPad will not boot. Through testing, i have determined that the problem occurs when the screen cable is attached to the 2 o'clock connector.
-
(It goes into a boot loop. and it's not the screen's fault - if you test this screen on a different iPad logic board,it works fine).
+
I checked the components connected to the FPC with a multimeter and found that the PP1V8_S3 rail is not a complete short circuit, but the resistance is unusually low, around 100 ohms. It looks like a half-short. I did not checked a short in any of the other components connected to the PP1V8_S3 rail.
-
I checked the components connected to the FPC with a multimeter and found that the PP1V8_S3 rail is not a complete short circuit, but the resistance is unusually low, around 100 ohms. It looks like a half-short. I did not find a short in any of the other components connected to the PP1V8_S3 rail.
+
The screen or the fpc connector is not the cause. If you install this screen on another iPad, the screen works fine. And I already replaced the fpc connector once, but the symptoms did not change, and the diode values on the other connector pins are all fine except for the pins connected to PP1V8_S3.
Anyway, when I remove the screen, it boots up normally again, and I also measure 1.8v on the PP1V8_S3 rail. However, when I reinstall the screen, it starts the boot loop again.
-
I injected current into the PP1V8_S3 rail through a DC power supply, and to my surprise, one of the RAMs on the A12Z AP is generating heat. I didn't find any heat on the other PP1V8_S3 components.
+
I injected current into the PP1V8_S3 rail through a DC power supply, and to my surprise, one of the RAMs on the A12Z AP is generating heat. I didn't checked any heat on the other PP1V8_S3 components.
Could this be a problem with the RAM? If the RAM is the problem, it seems impossible to repair.
Without the screen, it boots up and works fine, but with the screen installed, the iPad will not boot. Through testing, i have determined that the problem occurs when the screen cable is attached to the 2 o'clock connector.
(It goes into a boot loop. and it's not the screen's fault - if you test this screen on a different iPad logic board, it works fine).
I checked the components connected to the FPC with a multimeter and found that the PP1V8_S3 rail is not a complete short circuit, but the resistance is unusually low, around 100 ohms. It looks like a half-short. I did not find a short in any of the other components connected to the PP1V8_S3 rail.
-
Without the screen, a 1.8V voltage is normally output from the rail.
+
Anyway, when I remove the screen, it boots up normally again, and I also measure 1.8v on the PP1V8_S3 rail. However, when I reinstall the screen, it starts the boot loop again.
I injected current into the PP1V8_S3 rail through a DC power supply, and to my surprise, one of the RAMs on the A12Z AP is generating heat. I didn't find any heat on the other PP1V8_S3 components.
Could this be a problem with the RAM? If the RAM is the problem, it seems impossible to repair.
Without the screen, it boots up and works fine, but with the screen installed, the iPad will not boot. Through testing, i have determined that the problem occurs when the screen cable is attached to the 2 o'clock connector.
-
(It goes into a boot loop where the charging current is activated, disconnected, and then repeated. and it's not the screen's fault - if you test this screen on a different iPad logic board, it works fine).
+
(It goes into a boot loop. and it's not the screen's fault - if you test this screen on a different iPad logic board, it works fine).
I checked the components connected to the FPC with a multimeter and found that the PP1V8_S3 rail is not a complete short circuit, but the resistance is unusually low, around 100 ohms. It looks like a half-short. I did not find a short in any of the other components connected to the PP1V8_S3 rail.
Without the screen, a 1.8V voltage is normally output from the rail.
I injected current into the PP1V8_S3 rail through a DC power supply, and to my surprise, one of the RAMs on the A12Z AP is generating heat. I didn't find any heat on the other PP1V8_S3 components.
Could this be a problem with the RAM? If the RAM is the problem, it seems impossible to repair.
[image|3370561]
[video|6028]
iPad Pro 11 Gen 2 (A12Z) model.
Without the screen, it boots up and works fine, but with the screen installed, the iPad will not boot. Through testing, i have determined that the problem occurs when the screen cable is attached to the 2 o'clock connector.
(It goes into a boot loop where the charging current is activated, disconnected, and then repeated. and it's not the screen's fault - if you test this screen on a different iPad logic board, it works fine).
I checked the components connected to the FPC with a multimeter and found that the PP1V8_S3 rail is not a complete short circuit, but the resistance is unusually low, around 100 ohms. It looks like a half-short. I did not find a short in any of the other components connected to the PP1V8_S3 rail.
Without the screen, a 1.8V voltage is normally output from the rail.
I injected current into the PP1V8_S3 rail through a DC power supply, and to my surprise, one of the RAMs on the A12Z AP is generating heat. I didn't find any heat on the other PP1V8_S3 components.
Could this be a problem with the RAM? If the RAM is the problem, it seems impossible to repair.