Apple logo boot loop - only with drained battery
Hi out there.
I am currently working on trying to save a water damaged iPhone 5C.
When I received the phone, the phone went into an Apple logo boot loop, as soon as the charger was connected, so I assumed that the logicboard was not completely fried.
The first thing I did, was to remove the logicboard, desolder all EMI shields, and cleaned it using 99% IPA. Unfortunately I do not own an ultrasonic cleaner as of yet.
The only area which showed any signs of corrosion was around some backlight components in the top left corner - and seeing as I was able to see the Apple logo, the backlight was working fine.
When the phone was prompted to boot using the power button, nothing happened, which together with the boot loop, lead me to believe that the battery was dead.
I then proceeded to replace the battery, and wouldn't you know - the phone booted fully to the home screen.
I did however notice, that the battery drainage was a little more than usual. i.e. it would drain the 100% charge in 4-5 hours when it was not used. If I left the phone for a longer period of time, the phone would drain the battery to 0V. If I proceeded to charge the battery, the phone would startup in a boot loop again. I the charged the same battery in another phone and reinstalled it in the phone and the phone booted fully once again.
I assume that something is drawing current from the battery even when the phone is turned off, but I have no idea what it could be - does anyone have any experience or good advise?
Is this a good question?