iPhone 6 water damage with VCC_MAIN short

Hi all!!

I have an iPhone 6 that took a bath in the toilet. Before it turns forever into a “$@$*!&” phone, I started to repair it but now I have few problems that maybe some good users can give some help.

Here are the steps I did so far:

1 - I have disassembled the main board and took all the EMI shields out. The damage is clear and I could see a lot of corrosion marks in some main capacitors.

2 - I started cleaning the hole board with a good and proper solution and everything looks fine now.

3 - Then I have tested the VCC_MAIN and it was short. I tested with a good power supply with the current limit set to 1.5amps and it was obviously short because the power supply reaches immediately the limited current.

4 - I took a look on the VCC_MAIN line and I found some dead and short capacitors which I have removed already.

Q1 - Now I have no short anymore but the VCC_MAIN resistance is between 20 and 30 ohm. Is this a normal value? Before it was 0 ohm = short.

5 - after that I tried to power the board again and the current dropped to 0.6amps, which obviously means that there's still a problem elsewhere.

6 - I have found that the U1501 was heating (no other IC was getting hot) by dropping some flux over it, even with those 0.6amps.

7 - then I have followed all the capacitors in the power lines supplied by that IC and I have found some more shorts which I have also removed, but still I am having a short somewhere and I dont know where.

Q2 - should I remove the IC U1501 and test the VCC lines before I end with no caps?

Q3 - After removing that IC the VCC_MAIN should give a higher resistance value?

What would the next steps?

Thank you very much and if you could help me I would really appreciate.

​