IPhone 7+ Will not turn on with battery.

[celltech]

I have an iPhone 7 Plus that customer brought in for no signs of life. Looking at the phone under the scope I found that Audio IC had been replaced and jumpers we ran on C12, F12, H12 and J12. These were all covered with conformal coating. I used a TriStar tester to find out that TriStar needed to be replaced.

After completing the TriStar job, the phone still would not boot. The DC power supply reading read .030 amps and was not moving. I examined the board more, removing plates and checking VDD_Main. I somehow overlooked Coil L1805 missing from the board near Audio IC. I replaced this Coil and finally got an Apple logo to appear. The phone was now long booting on the DC power supply. This is an Audio IC flag so I redid the Audio IC job only place back the C12 jumper. All other pads were fine.

Completing Audio IC, the phone continued to long boot but the phone did come on eventually when using the power supply. I used the TriStar tester again just to check for any charge issues. Now, Tigris failed. Changed Tigris and still had the same long boot. Ran the TriStar test again. Mosfit failed. So, I changed Mosfit.

The phone will long boot on DC Power supply but will not boot at all on any battery. All functions of the phone work fine once it is boots up with the power supply.

My question is why am I long booting and why is this phone not booting with any battery?

[Jessa_the_Professa]

Did you replace the audio ic or just reball the one that was on there?

I would not expect that tristar or tigris were damaged in a phone whose real problem was a missing cpu power coil L1805---that coil is lost from drop damage. My guess is that you have a replacement dock in that phone and it is messing up your tristar tester. Put that phone in a known good housing with a known good screen before doing anything else.