This blog will be going over 14 iPhone 7 logic board symptoms and their possible solutions. I say possibly because this blog will be going over micro soldering with the logic board. These are advanced techniques that can be used to debug your iPhone issues and it's recommended only for iPhone repair shops or people wanting to get into that business. We partnered up with www.newyorkliu.com to write this blog. Mr.Liu has been in the repair business for over 20 years with experience working in Huawei.
Wire both ends of R7704 together to fix.
Replace R4710 to fix this issue.
Test R2005 if it has 1.8v if it doesn't replace it.
Wire both ends of FL3908 together.
Run a jumper on point 2 to 3 on Q4001.
1. Test FL3911 both end if it has 5.1V and if it doesn't run a wire from one end to the other.
2.Test FL3909 if it has 5.7V if it doesn't run a wire from one end to the other.
Usual sympton is when you connect board to DCPS and the amps jumps way too much and the board starts to heat up.
First, test D3701 and D3702 using multimeter each side when reverse testing should be the same. If not the same, just replace them.
Replace R2201 to fix the issue.
Run a wire connecting A1 and A2 of U2501 but first test if both points give 2.95V if not run the wire.
Test FL3908 and FL3912 if they are 5.7V if not run a wire individually from end to other.
Replace FL3910 will fix the problem.
When testing with DCPS amps will be super jumpy.
1. Test J4502 touch Flex Connector point 35,37 and 39 will have no volt if it's bad.
2. Run a wire connecting both end of FL3901, FL3902, FL3903 individually or replace them individually to test.
3. If above testing does not solve, replace U3703 IC.
Run a wire from one end of FL3903 to the other end.
Run a wire from one end of FL2502 to the other end.
Posted on: Aug. 13, 2018, 1:52 p.m.