My iPad Mini 2 Refuses to Turn On - Page 1
Forum section: electronics / repair

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: January 31, 2016, 10:05:27 pm
content: So I got an iPad Mini 2 from a friend. It had a cracked screen and does not turn on. I have had this issue with my old nexus 7 2012 model, and the fix was to charge it for several hours. So I did. Nothing. After I brought it home, I took it apart. I am not going to have someone fix stuff like this for me, I can usually do it on my own. I already have a good tablet, thought I would fix this one up for my mom.Anyway, when I got inside, I disconnected the battery first, making sure not to damage the PCB around its connector. Then I disconnected the digitizer and LCD.After this, I peeled back the plastic insulation on the top of the battery to expose the two cell tabs. I took my multimeter to them, and there is the issue, the cell is at 2.5v. Too low for the device to even turn on, just like the issue with the nexus 7 2012. I thought.So I manually charge the battery up to about 3.6V, a voltage that the device should have no issues at least turning the screen on. Then I plug the LCD and digitizer back in, and then plug in the battery. But it is still dead. I have it plugged into my PC with a crappy third party cable (Brand new, just bought it from 7-11) and I am getting nowhere. The screen never turns on, my PC does not see anything plugged into the USB port.Any ideas? Does the charge controller on the lithium cell need a reset after it goes below a certain voltage? Is my 3rd party USB cable shot? What is going on here?

author: Supercharged
author_rank: Regular Contributor
timestamp: January 31, 2016, 10:29:56 pm
content: since it has a broken screen i think it is reasonable to say that it has been dropped. So the problem might be a broken connection to the charging port or some other physical damage that isn't obvious. The problem with those kinds of products is, that they are really hard to troubleshoot, the only way to fix it if you find the fault is to replace the faulty part.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: January 31, 2016, 10:39:31 pm
content: Quote from: Supercharged on January 31, 2016, 10:29:56 pmThe crack was caused by a sharp impact on the screen. The corners are in good condition. Anywah, bit of an update. I took it apart to see if it had charged any more from being plugged in, and it was still where I left it. So I tested the voltages on the battery connector and couldnt find anything of use. So I probed around thd battery board, and for some reason, the BMS board seems to have randomly sprung into life! I have power on the connector now. Still no activity on the screen, but now thr CPU or something seems to be getting a little warm and the battery voltage is rising. So I think this is progress.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: January 31, 2016, 11:53:42 pm
content: So I still cannot get it to wake up. When I connect the battery to the motherboard (with my charger connected to the cell) the voltage drops a bit. Then, when I plug the lightning connector in as well, the voltage rises a bit. So I tried the reset "hold the power and home buttons" thing, and the voltage spikes up a little bit, as if the device does actually "reset"

author: Howardlong
author_rank: Super Contributor
timestamp: February 01, 2016, 12:09:59 am
content: Although like you I fix the odd bit of Apple stuff myself, and when not doing that I also design and build stuff that goes into space, sometimes I have to know when to quit and get the nice man at the local fix it store to do it for me. Much as it hurts my manly manness, I find you've just gotta know when to let go. But when you do, ask the kind man how he fixed it, so next time you can do it yourself.To put into perspective, you won't find many Bugatti mechanics who can fix a Tesla.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: February 01, 2016, 01:22:03 am
content: Quote from: Howardlong on February 01, 2016, 12:09:59 amI popped the can off of the CPU section and the chip next to the CPU is extremely hot. I looked again and its actually a first gen ipad mini. I am not an apple user so I am not an expert on these thingsI am going to sell it for scrap price, I got it for free anyway. Would cost too much to repair than its worth

author: Duffrageous
author_rank: Newbie
timestamp: February 02, 2016, 10:44:48 pm
content: Street value of a working unit is probably $125-$150, broken--probably around $50. Assuming the white water indicators haven't turned pink, you've greatly increased the chance of a repair. The CPU is hot probably because the power IC is malfunctioning and drawing too much power. I could give you more info like a diagram on this repair if you're up for it.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: February 02, 2016, 10:56:37 pm
content: Quote from: Duffrageous on February 02, 2016, 10:44:48 pmThanks for the help, but its honestly not worth my time right now to fix. Thanks though!

author: SaabFAN
author_rank: Frequent Contributor
timestamp: February 02, 2016, 11:03:35 pm
content: A chip inside the can getting really hot sounds like a short-circuit inside the LCD. As far as I know, the regulator for the LEDs inside the display has no current-regulation (that's why it kills itself when power is applied but there's no display connected) and so it's probably dumping as much power into the shorted backlight as it can.If you have an LCD ready, you might be able to test this, but from the looks of it, I think currently the best option is to sell it as non-working on ebay and buy components for a Raspberry-Based tablet. Those things are way more interesting anyway

author: RobII
author_rank: Regular Contributor
timestamp: February 03, 2016, 03:51:30 am
content: Not sure if you tried this though it seems silly. Plug ot into a computer. My wifes tablet battery went completely dead. Even plugged in to the charger, nothing. Plugged it into the usb on my pc and it started charging and woke up.Sent from my GT-P5210 using Tapatalk

author: wraper
author_rank: Unknown
timestamp: February 03, 2016, 11:44:25 am
content: Did you try to flash the firmware? Does iTunes see it if you try to set it into DFU mode?

author: itechva
author_rank: Newbie
timestamp: February 06, 2016, 03:03:04 am
content: The issue is most likely the PMIC, which is a known issue for all first generation ipad minis. Replacing it is a b*tch because of the underfill, but it's doable. I don't think you will find anyone out there crazy enough to do it for you because the time cost greatly outweighs the cost of the device. If you want to give it a go yourself, you can find this chip on aliexpress for about $5-$7 a piece.I've heard that Apple will give you a $100 credit if you bring it back to them in store.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: February 06, 2016, 06:50:04 pm
content: Quote from: itechva on February 06, 2016, 03:03:04 amYa, the yellow chip there is what burned my finger -_-I doubt it would be worth anything as the screen is broken as well and I have most certainly voided the "tamper evidence" things, because the tape on the battery is peeled back (so I could charge it) and the tamper sticker on the shield is... well... tampered with.