1. Take out the old man's mobile phone and mobile phone card first. As shown in the figure.

2. Then remove the phone case from the back of the old phone. As shown in the figure.

3. Take out the battery again. As shown in the figure.

4. Then the copper core of the mobile phone card faces down. As shown in the figure.

5. Then insert. As shown in the figure.

6. Finally, put the battery and mobile phone case back. As shown in the figure.

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If the old machine can't make a phone call, the specific solution is as follows:

1, check whether the mobile phone is in flight mode;

2. Check whether the cell phone signal is stable. If the network signal is not good or there is no signal, please turn off the phone and restart, and search the network again. If it fails, it is recommended to take out the SIM card and try to insert it again.

3. Check whether the mobile phone has enough balance;

4. If you can dial some fixed numbers, check whether the fixed dialing function is started. It is recommended to disable this feature.

5. Check whether the call barring function is set. If so, please cancel and try calling.

6. Replace other SIM cards;

7. Back up data (contacts, text messages, pictures, etc.). ) and restore the factory settings.