The Apple iPhone 5s was announced on September 10, 2013. Repair of this device is similar to the previous models, and requires screwdrivers and prying tools. Available as GSM or CDMA / 16, 32, or 64 GB / Silver, Gold, and Space Gray.

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CPU is getting abnormally hot


So my friend dropped her 5S in a pool and I have no idea if she immediately turned it off and put it in rice or not. She gave me her 5S in hopes of reviving it. I took out the logic board, soaked it in 90% isopropyl alcohol for a day, replaced the battery, and cleaned out any corrosion that I saw. I reassembled everything back together and notice that the middle of the screen has lost touch functionality and that the CPU was getting abnormally hot and killing the battery life, which to me indicated a short circuit. I tested this with 2 other spare 5S screens I have on me and they both exhibited the same problems.

Since I'm not an expert with SMD soldering and risk messing the board up even more, I bought another 5S logic board on eBay that had no water damage or any problems. I install the board and the screen has full touch functionality and everything went well. Except that the CPU is still getting abnormally hot and making the battery life really bad. It gets too hot to touch the phone sometimes and it stays hot even if the phone is sleeping so this is not the normal operating temperature of the phone.

So I think to myself, what could possibly be making this CPU heat up so much? Could it be the dock connector? Or is it the replacement battery that could be making it do this? I replaced the logic board and inspected it to make sure it wasn't water damaged which it wasn't. It just confuses me so much right now. All help would be appreciated.

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That sounds interesting. Typically, once a phone has been water damaged, you would have to change both the battery and the dock connector to ensure that the phone is not damaged further.

If I were you, I would change the dock connector (and battery if you have not already) before going any further. If that does not help, you should try to disconnect the powerbutton flex, start the phone and see if the problem persists.

Certain programs, such as GPS apps, can cause the phone to heat up abnormally. Did you restore her phone after installing the new logic board? If so, try to restore it to factory settings.

Hope this helps? :)

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I have already restored the phone and set it up as a new iPhone. It's been in airplane mode for a good 4 days now and location services is off and the cpu is still heating up abnormally. Like it's just the cpu, nothing else. I've also tried disconnecting the home button flex cable and booting it up and it was pretty much the same. I've already replaced the battery and I will try replacing the dock connector and see if that resolves the issue. I'm hoping it will.


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