In IPhone sometime mobile refuse to accept sim card it shows no service message instead of network indication. In some case we get network error that automatically no service message appears and we can’t connect call this is due to sim card IC problem
For this problem solution we have to first check that weather flight mode is set to off mode then try following methods:
1. First try to change sim card then check problem
2. Secondly change the sim card jack and check for solution
3. If no success then check track line continuity from one to one sim connector to exact sim card internally circuit point on pcb carefully .
4. Those sim card connector track are shown in image with different color and numbering below :
5. If we found any track missing here then apply jumper as shown in image carefully.
After all done mobile will accept sim card properly.
During track line checking on points on pcb we should have full knowledge of internal sim circuit point because wrong jumper can destroy sim circuit completely.