This is another solution for sony ericsson xperia x1 with insert Sim card problem or it does not detect or does not recognize any working sim card inserted to it and it shows," Insert Sim Card" on the display.
SE Xperia X1 Insert Sim card repair solution
You may check and replace the 10 ohms resistor as shown on the solution above, then ensure that SIM card pin connectors were all cleaned, replace if misaligned or damaged.
