He already made appointment with me so that i could check and repair on same day.
Below are the steps how i teach my staff to repair.
As usual, must need to opened it and put under microscope to check.
- Check the home button flex.
- Check the FPC connector for home button / Touch ID. (iPhone 6 is J2118)
Measure the voltage by using multimeter.
Other pins just measure resistance.
Flex is good, no broken..
BUT THERE IS A BURNT MARK under the home button.
Found the shorted capacitor. Need to replace it.
But better find out why... So continue to measure FPC connector which supply power to the Touch ID.
Found out 1.8 is over power.
Check the iPhone 6 schematic to find which ic is supplying the 1.8.
In diagram look for keywords PP1V8_MESA_CONN. Search where it leads.
Found it. It's U2100.
From the diagram you can see U2100 job is taking 3V and cutting down it's current to 1.8V and supply into FPC.
Mean this IC is not doing his job. Need to replace it too. (Some technician will just borrow a 1.8v from another spot and jumper to here. But i prefer teach my staff to repair it as original designed)
From the diagram you can see U2100 job is taking 3V and cutting down it's current to 1.8V and supply into FPC.
Mean this IC is not doing his job. Need to replace it too. (Some technician will just borrow a 1.8v from another spot and jumper to here. But i prefer teach my staff to repair it as original designed)
Replaced burnt capacitor on Home button flex and U2100 on PCB. Then Touch ID is resurrected.
By just using basic resource and schematic can do the job without problem.
DONE!!
