The solution below shows the connection line paths of the Samsung S3850 SIM card connector and which components needs to be check first.
Samsung GT-S3850 Insert SIM card Problem Solution
Samsung GT-S3850 Insert Sim Solution
Samsung GT-S3850 Sim Card Connetcer Pin Ways Tracks Repair
If the phone doesn’t detect any working sim card inserted to it, try to clean the sim card pin connector first.