iPad A2378 dead no charging

[kingskie]

Hello everyone,

i have an iPad A2378 dead no charging.
disassembled and found out that 343S00389-A0 ic was hot so i took it out. after that i measure but the caps ( you can see in the picture i attached) still short to ground.

does anyone has a clue?

[elecsoluces]

Re: iPad A2378 dead no charging

It is a Vcc High short first check Vcc main (tantal cap near the ic you have removed)

[kingskie]

Re: iPad A2378 dead no charging

It is a Vcc High short first check Vcc main (tantal cap near the ic you have removed)

do you have boardview for this type? i checked these 3 tantalum caps not shorted.

i tried inject 1V 3amps but nothing's get hot

[elecsoluces]

Re: iPad A2378 dead no charging

Boardview is available with paid software.
You can find schematics for this board.
Vcc main is not shorted it is a Vcc high short.
Many IC are connected to this line, inject voltage to find the shorted component

[kingskie]

Re: iPad A2378 dead no charging

Boardview is available with paid software.
You can find schematics for this board.
Vcc main is not shorted it is a Vcc high short.
Many IC are connected to this line, inject voltage to find the shorted component

already tried inject voltage but nothing is hot.

[elecsoluces]

Re: iPad A2378 dead no charging

Have you removed the two top shields? There is a lot of connection in this area.
What tool are you using for heat detection?

[kingskie]

Re: iPad A2378 dead no charging

Have you removed the two top shields? There is a lot of connection in this area.
What tool are you using for heat detection?

do you mean the shields that i circle in the picture?

[elecsoluces]

Re: iPad A2378 dead no charging

No Vcchigh in you red circle.

[kingskie]

Re: iPad A2378 dead no charging

No Vcchigh in you red circle.

nothing getting hot here also..

[waterchill]

good day, I have same iPad which is dead. Current draw is 0,5A@5V when battery is connected and 0,1A without battery. Didn't found a short, I can measure 3,7V and 5V around the PMIC. With IR cam the PMIC gets slightly hot about 30°C with battery connected. Checked a lot of caps, no short. What do you think is it worth to change the PMIC or other ideas? Thanks

[mon2]

Check to be sure the charge port contacts are clean and without debris.

review this video which may help:

https://m.youtube.com/watch?v=ErzWDwPmZnU

[waterchill]

Thank you. Contacts are very well the iPad is like new. Just measured the battery voltage, it's at 3,66V. I charged the iPad the whole night but it hasn't charged the battery. I don't know if this Generation iPad can show the Apple Logo for short time without battery connected like the older models? I found schematics for this iPad but missing boardfile. Anyone have it?

[mon2]

The current draw is too low for this logic board to be booting. Would you know of the history of this board? Alex (Northridge) has a number of good videos on ipad repairs - so does Ben from Germany (he is the one with the manbun). You should be ok to just power from the external power adapter but as noted, at 0.5A, not enough to power the board.

Q1: Upon attaching the power adapter, does this current draw spike immediately to 0.5A or climbs up slowly? If immediate, you have a shorted part.
Q2: What is the logic board # on the board? Should be 820-*** format.

Personally, ipads really test my patience and often decline their repair but do review the details. Check the video from YT which shows a blown ferrite bead for the LCD display and a defective backlight diode.

[waterchill]

Can you point me where I can find the # of the logic board? Actually cannot find it. This iPad died over night for some reason with plugged in charger. With battery connected, current goes immediately to 0,5A. With no battery connected it goes to 0,1A. Actually I have connected an iPad boot cable and the iPad is booting into system. So it looks like the battery is faulty?

[mon2]

Actually I have connected an iPad boot cable and the iPad is booting into system.

I have same iPad which is dead.

???

[waterchill]

Sorry but I got this idea occasionally. Normally an iPad starts up for seconds without battery. It seems that an M1 iPad cannot do tzhis. I thought battery is ok because it have over 3,6v. I will try now with new battery

[waterchill]

Today I tried new battery and the iPad is booting into system. Can use it like normal. But in the moment I plug in the charger iPad is freezing and goes black. Unconnect and connect battery again same game. The battery is charging for some seconds with about 30W but after some seconds it goes to 0,5A and stuck. I reflowed the PMIC without result. So the only thing I can do here is change the PMIC. Other ideas? Thank you

[waterchill]

I changed the PMIC today with same result. It works on battery, if charger plugged in iPad freeze and goes black.

[mon2]

So this is a USB Type C charger port? Have not seen these in the shop yet. You have a CD3217 power delivery controller onboard so the same investigation as the macbooks will apply.

Remove all power -> meter in DIODE mode. Locate and review connector J3700. Lift off the charge port cable which should be removable. Then measure each signal on this J3700 connector in diode mode. Red meter probe to ground; black meter probe to pin to test.

Post each measurement. Checking for a defective signal line. Something between the chargeport and the CD3217 is to blame.

[waterchill]

So this is a USB Type C charger port? Have not seen these in the shop yet. You have a CD3217 power delivery controller onboard so the same investigation as the macbooks will apply.

Remove all power -> meter in DIODE mode. Locate and review connector J3700. Lift off the charge port cable which should be removable. Then measure each signal on this J3700 connector in diode mode. Red meter probe to ground; black meter probe to pin to test.

Post each measurement. Checking for a defective signal line. Something between the chargeport and the CD3217 is to blame.

Thank you for the hint. I have checked all pins, all values looks ok. I have here an iPad Pro 11" 2nd gen which have same chip. The values are all the same. Also checked with usb-c tester, also everything is ok.