https://youtu.be/aIq_DkSqkAs

Disclaimer, I usually do a laptop repairs so mobile repair is not my specialty, sorry if my approach you found somewhat dumb.

the ipad comes with no display problem with 0 amp current draw, upon checking i found the voltages around the board (when the power button is pressed) is pulsing like 3v and goes back to 0v and so on.

this symptom is look like the ipad itself is trying to boot but failed, then i began to search if there is a short circuit across the board, alas there is no short at all and all voltages look like present and healthy except for the pulsing issue.

*the pulsing issue persists when the ipad is only powered by the battery. (with and without the power cable attached)

because i have no idea where to start diagnose further, i read in many forums that U2 tristar is likely to be the culprit, with that idea I tried to replace the tristar with a new one and the problem is of course still persist.

what i have already checked are

• the battery is known good
• charging port no problem (tried another one)

* no short circuit

• power button is good i think (i've tried jumper it from the on off from the power button connector and the problem still the same)

i think the real culprit will be U8100 which is the PMU because the PMU is responsible for power delivery to those component on the logicboard (right?) but im not sure because i don't have enough evidence yet to replace that PMU

or maybe the communications board (where the baseband chip located i suppose) can cause the issue?

⟐ Answered October 08, 2025 at 19:04 MST

⟐ Answered July 22, 2020 at 18:16 MST

Got an iPad here that the customer said its just not powering on. I plugged it into the PC and opened 3uTools and it wasn't turned on. I charged it for more than 24 hours waiting for life but there was none. I changed the charging port and still made no difference. So I tried a new LCD whilst it showed the Apple logo (White) it went back off after it flashed about 3 times. I have since changed the battery too and It seemed to have more power. I was able to reflash the iOS thinking it could just be a bad software glitch and it seemed to have worked. I can setup the iPad as new and seemed ok.

But after the setup when the screen timeout kicks in I cannot get it to turn the display back on. iTunes and 3uTools says its turned on but there is no display. I've tried 2 new screens now and its still the same.

Any Ideas?

⟐ Answer accepted October 24, 2019 at 16:52 MST

⟐ Commented October 22, 2019 at 14:28 MST

I have an iPad 3 that works just fine but has begged me for retirement :)

I also have an iPad 4 with broken glass that has stopped working properly (at least it can't charge but in other cases has shown no faults so I suppose its logic board is ok and it might need just a connector unit or maybe battery replacement).

So I found that I can simply replace the screen from 3rd to 4th.

And the questions are

- what should I check to locate the flaw that prevents iPad 4 being charged?

- can I replace the battery from 3rd to 4th if it's the problem?

⟐ Answer accepted October 08, 2019 at 19:06 MST

replaced touchscreen with ifixit touchscreen and home button works but the touchscreen doesn't function at all. The digitizer seems to work fine. I think the touch screen is bad or I'm not getting the ribbon cable back in correctly for touchscreen. Can I test the touchscreen without installing it? Is the touchscreen independent of the digitizer ? The one issue I have is the touchscreen ribbon cable will not sit passively like the oem and thus the touchscreen does not passively seat even though the cable is connected.

There are plenty of how to videos to break down but "just reverse the steps to put back together " makes actual repair without expert help very difficult.

⟐ Answer accepted August 07, 2019 at 18:55 MST

⟐ Answer accepted February 16, 2019 at 5:48 MST

⟐ Answer accepted February 16, 2019 at 0:02 MST

Thanks for any help.

⟐ Answer accepted November 18, 2018 at 8:06 MST

I recently replaced a digitiser and LCD in an iPad 4. The repair was successful - until a month later the client has came back to me and there's no display, it's responsive to iTunes so it is not dead. I can only think of the proximity sensor? It's just a black screen.

Where abouts is the proximity sensor located and is there anyway of just disabling it so the display can work again?

Thanks in advance.

⟐ Answer accepted September 20, 2018 at 5:22 MST

my Ipad 4's battery has reached 0% two days ago. As usual I attached it to the original charger (with non-original cable) but it would neither charge anything (just stay as in the attached picture) or boot. After inserting the cable and after pressing the power button the attached picture appears on the screen for two seconds but nothing else. It stayed on the charger for around 24h now without any changes.

I have already researched a little and have tried a second cable, charging dock and cleaned the lighting adapter (nothing noticable came out). I also tried the different combinations of pressing the power and home button, but the Ipad would just stay in the state as in the picture.

I have run over this tutorial from 2012: Ipad Dock connector no longer working

Does anyone know if this procedure would be applicable to the Ipad 4 too? Any other ideas?

Thank you a lot for your help!

Best regards

SadIpadUser

⟐ Answer accepted September 09, 2018 at 10:14 MST

⟐ Answer accepted July 27, 2018 at 20:48 MST

⟐ Answer accepted April 26, 2018 at 6:36 MST

I've tried to plug in the phone jack as suggested in another post, no success.

I've also tried the hairdryer trick to heat up the SIM chip tray aperture that was mentioned somewhere else, still wouldn't work.

And of course I tried different cables and different USB ports - I had used the same cable and USB port to restore my iPhone minutes early to check that everything was fine and it was.

Nothing worked, iPad remains stuck at about 75% and show error 50 when recovering… Could it be some hardware issue and if so, how to fix it…?

Gave up, will sell it for parts...

Any way of figuring out the capacity (Gb) with the serial number?

⟐ Edited by author March 07, 2018 at 2:44 MST

⟐ Answered January 25, 2018 at 9:32 MST

⟐ Commented January 20, 2018 at 13:21 MST

⟐ Commented December 26, 2017 at 12:13 MST

⟐ Edited December 24, 2017 at 10:54 MST