Android phones can't access the 4g network. It is said that the motherboard is broken. How to repair the motherboard without changing it?

If the mobile phone cannot use the 4G network, we recommend that you:

1. Whether to use the mobile phone card with 4G service, I suggest you contact the network operator to open 4G service.

2. Check whether the 4G network mode is enabled: Settings-Connect-More Networks-Mobile Networks-Network Mode-Select the 4G/3G/2G(LTE/WCDMA/GSM) network mode (some mobile phones/tablets do not support changing the network frequency band).

3. Confirm that the location has 4G network coverage.

4. Try to shut down and restart.

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

If the problem still exists, it is recommended that you take the purchase invoice, maintenance card and machine to the local Samsung after-sales service center, and professional engineers will help you test it.