Minho

Alright, seeing as how I am always answering questions here, I thought I'd reverse the roles here for a bit of fun. I have...

Hello Mac Experts (@mayer, @danj , @reecee and others) I have an iMac 27", Late 2012 that is not booting properly. It is...

This iPad has a dead zone on the left edge of the digitizer, about 5 mm from the edge. I proceeded to do a standard...

Hello Mac Guru's (talking to you @mayer, @danj, @reecee)! I have another MacBook Air A1466, this one an early 2015. The...

Hi everyone. This is a follow-up to my MacBook Air 13” (2014) – Water Damage, will not power on. Thanks to everyone who...

Hi everyone. I have a water damaged (tea) MacBook Air that was dead as a doorknob. No light on the MagSafe, no fan or...

It sounds like a dead battery…however before changing the battery, consider this: (1) Always try another Lightning cable and charger, preferably Apple original or MFi certified units. (2) The Lightning cable 8-pin connector should be sitting flush with the housing and completely inserted. If it is not, there could be lint/dust/debris inside the port impeding a proper connection. You can clean it out with a toothpick, fine point tweezers or a dental pick. Just be careful not to damage the pins inside the Lightning Port. (3) Change the battery. The battery is the weakest link in the entire phone and certainly for charger related issues. It is also the easiest thing to replace. Use a battery utility, such as coconutBattery (for Mac) or 3uTools (for Windows) to test the battery prior to removal. Anything less than 70% of design capacity will require replacement. (4) If the battery is in good condition, you can use a USB Ammeter to determine if the phone is really drawing current when it says it's charging. If...

What happened in the days leading up to this issue; was the phone dropped, repaired or came into contact with water? This could be as simple as a bad battery (although iFixit batteries are usually very good) or it could be a logic board issue. You could try disconnecting the screen and cameras from the logic board (battery first!), leaving only the board, dock flex and battery and then see if the phone will be recognized by an iTunes enabled computer. If it doesn’t see the phone, then it is most likely a logic board issue. If the phone does boot, then add one flex at a time until it stops working to determine the faulty part (again, always disconnect the battery).

The iPhone X has extraordinarily thin logic boards, two of them sandwiched together. They are very susceptible to cracked solder balls, either in the interposer (which connects the two layers) or on the boards themselves. At this point, you will need to troubleshoot the phone with the notion that this is a hardware issue. It could be modular in nature, i.e., the screen or a camera or other flex or it could be logic board related. You could bring the phone to it’s essentials, board, battery and charge port, and then connect it to an iTunes enabled computer. If the computer recognizes it and maintains a solid connection, then the issue is probably modular in nature. Otherwise, it is logic board related and will need to be looked at by an experienced micro-solderer.

This could be a charge circuit issue. By putting in a charged battery, your phone worked but once the battery was uncharged, the phone appeared dead but in reality may just have been incapable of charging the battery. Here are some steps you can take to help in troubleshooting this issue. (1) Always try another Lightning cable and charger, preferably Apple original or MFi certified units. (2) The Lightning cable 8-pin connector should be sitting flush with the housing and completely inserted. If it is not, there could be lint/dust/debris inside the port impeding a proper connection. You can clean it out with a toothpick, fine point tweezers or a dental pick. Just be careful not to damage the pins inside the Lightning Port. (3) Change the battery. The battery is the weakest link in the entire phone and certainly for charger related issues. It is also the easiest thing to replace. Use a battery utility, such as coconutBattery (for Mac) or 3uTools (for Windows) to test the battery prior to removal. Anything...

If you’re going to ask a question, giving more background information will get you better answers. Is this before or after a repair? Was the phone dropped or came into contact with water? Is this your phone or did a customer bring it in? As it stands, no backlight could either be a bad screen or damage to the backlight circuit (was the battery disconnected prior to a screen replacement for example).

It sounds like a logic board issue so if you already know someone who can troubleshoot this then that should be your next step.

Based on what you say, it appears the logic board was damaged. The iPad should boot up without an LCD and Digitizer so if it is not being recognized by iTunes, then the issue is most certainly on the logic board (check you cable and computer with another device just to be certain). It’s very important to isolate the battery from the logic board when doing repairs. The typical issue is usually the backlight circuit but just about anything can go sideways.

Sounds like you may have a defective replacement battery or something on the logic board was damaged either during the replacement or was the root cause for you needing to change the battery in the first place. If the old battery still worked, even if with reduced capacity, I would install it to see if the problem persists. You need to eliminate some variables here and give more information on why you had to change the battery in the first place.

Unfortunately, this is not possible. The iPhones are engineered to be totally integrated so you cannot mix and match processors, screens, cameras or anything else really. Some batteries will fit from certain models to another and you could probably get an iPhone 7 screen to work on an iPhone 8 (I’ve never tried but I have seen a few answers in that regard) but it doesn’t give you anything fundamentally better than what you already have.

The iPhone 7 series of devices have proven to be very unreliable, suffering from flex-based issues similar to the iPhone 6 Plus (Touch Disease). On the iPhone 7, the fault line runs along the top of the SIM card reader and affects the Baseband CPU and Audio IC. Any short copper traces running perpendicular to the fault line while connecting to micro-BGA pads, is subject to failing. On the Audio IC, this particularly affects the C12 pad/trace although there are 4 pads/traces along the fault line. Of those four, the C12 pad (I2S_AP_TO_CODEC_MCLK) is the most critical as it is a communication protocol line between the CPU and the Audio IC. This can happen seemingly out of nowhere and usually follows a reboot of an affected device, like when you shut it down to repair it. Sometimes the removal of the screen gives the logic board that last “flex” that puts it over the edge. Once rebooted, the phone exhibits symptoms that were never present before. '''' Here are the typical symptoms, as collated by the repair...