Malfunction Phenomenon
The ringtone can’t work on the phone.
Trouble Shooting
iPhone X Ringtone Not Working issue.
- First, take apart the phone and run the cosmetic inspection of the motherboard. The cosmetic looks fine.
- Then get the display assembly installed and connect the battery connector with DC power supplies, check the current reading on the ammeter is normal.
- Then replace the external accessories, but the issue still remains.
After that, we can detach the two layers of motherboards from each other and measure the diode value of corresponding pins to the ringtone on the middle frame. The measured value of pin 41 is 4600 (the normal value is around 500), which is abnormal.
Then we detach the middle frame from the motherboard and find the bonding pads had been corroded, especially pin 41.
From the circuit diagram, the pin 41 signal is PP1V8_AUDIO_VA_S2, which is outputted from pin M3 of U2700. It means that the power supply voltage(1.8V) of the Audio is abnormal. So we can conclude that the fault is related to pin 41 on the middle frame.
You can also refer to the below schematics to check the details.
So we scrape new pad with a knife and put some tins with soldering iron, then put back middle frame and make the upper layer and lower layer solder together. Then assemble it and test again, the problem resolved.
iPhone X Motherboard Repair Course
