iPhone 6s has been no serviecs fault maintenance

iPhone 6S has always been no serviecs, which shows that there is something wrong with the signal reception. Find the common points of the signals received by these three operators, namely RF,ANT Switch, and after replacing RF, the fault is relieved.

iPhone 6s has been no serviecs fault maintenanc

Machine model: iPhone 6s
Malfunction: the mobile phone has been no serviecs.
Maintenance process:
The mobile phone has been no serviecs, and other functions are normal. There are Baseband,IMEI and no serviecs, but the operator selected manually has no response. All the cards of the three operators have been tried, and all the mobile phones have been no serviecs.

iPhone 6s no serviecs fault maintenance Figure 1.

Explain that there is something wrong with the signal reception. Find the common points of the three operators receiving signals, namely RF, ANT Switch, and after replacing RF, the fault is removed. At this point, iPhone 6s has been repaired by no serviecs.