How to Fix iPhone 8 No Baseband No Signal Problem

We have received a defective iPhone 8 motherboard from our customer and he claimed the problem is No SIM error. With our troubleshooting, we discover it’s not invalid SIM but baseband problem. In the article, we will share troubleshooting method of iPhone 8 no Baseband no signal problems after dropping. Hope you enjoy our sharing.

1. Prepare a working station and some phone repair tools.

- Aluminum Alloy Microscope Pad

- Phone disassembling tools

- ZXW online account

- DC power supply

- Digital multimeter

- Microscope

- Phone rework station

- Other tools 2. Now we need to confirm the failure, we need to check if it's baseband problem (no baseband) or signal problem (no signal).

3. Use phone disassembling tools to disassemble the iPhone 8, remove the iPhone display assembly, disconnect the iPhone battery, and then take out the iPhone 8 motherboard.

4. If the iPhone 8 shows no baseband

- First use Fluke 15B+ digital multimeter to measure the capacitors around the iPhone baseband power to check if it's short circuit; if there is no short circuit, then we can directly replace the iPhone RF IC. During this process, there are two things we need know.

- One is we need to care temperature for removing the RF IC by hot air gun, if the temperature is too high, it's easy to damage the IC, so we'd better use low temperature solder paste, and keep hot air gun about 300 degrees.

- The other is that we need to pay attention to the resistor r808, if this resistor r808 is virtually welded, it will cause the iPhone to have no baseband.

5. If the iPhone 8 shows no service

- One the fault for iPhone 8 no service is that it keeps reporting SIM card when it's not installed.

- This problem mostly is caused by the disconnection between high frequency diversity receive and low frequency diversity receive communication circuit, the circuit between low frequency diversity 7.8.9.10 Pin and high Frequency Diversity 25.26, 27.28 pin are disconnected.

- We can fix it by soldering a jump wire. Use JBC CD-2SHE Soldering Station to solder a jump wire to connect them. I hope the repair method mentioned above can help you. If you have more effective methods to solve this problem, please share with us in the comment below. Thanks for reading.