How to Fix iPhone 7 No Service/No Signal | Chip Level Repair
If your iPhone shows “No Service” in the status bar (even if baseband is available), it can caused by either software or hardware issues. We have received an iPhone 7 from our customer claimed it has “No Service” problem, In this article, we will share how to troubleshoot and fix iPhone 7 no signal/no service through chip-level repair, hope you enjoy our sharing.
Step 1 Function Test
Insert the SIM card, power on the iPhone and turn off the Airplane Mode, the iPhone shows No Service. Open Settings＞General＞About, both baseband (Modem Firmware) and ICCID has data, proving the iPhone can read the SIM card.
Step 2 Diagnosis
Measure the diode resistance of the RF circuit power supply and discover the diode resistance of C7117_RF is measured short circut. As the power amplifier IC QPOET_RF provides power for signal amplifier and the power goes through C7117_RF, therefore the C7117_RF short circuit will cause no signal.
Step 3 Troubleshooting
Remove the power amplifier IC QPOET_RF and remeasure the diode resistance, the diode resistance remains short circuit. Remove the low-frequency amplifier IC and remeasure, the diode reisstance showed normal. Therefore, it’s the defect low-frequency amplifier IC that caused the short circuit
Step 4 Repairing
Replace a new good low-frequency amplifier IC and remeasure the diode resistance of C7117_RF. The diode resistance showed normal.
Step 5 Reassemble & Test
Reassemble the motherboard then power on the iPhone, signal backs normal, repair completed.
Please refer to below detailed video:
Connect with us
On Facebook, LinkedIn, Twitter, YouTube, Instagram
Questions are utterly welcome!
Tools and Materials Used in This Video:
Microscope
Soldering iron
Multimeter
Tweezers
Solder flux
Hot air gun
Motherboard fixture
Desoldering braid/ solder wick
PCB cleaner
Soft brush
