1. There is no sound from the handset. You cannot hear the other party's voice during a normal call. After disassembling the phone, first check whether the contact point between the handset and the front camera cable is abnormal. If it is normal, replace the handset. If there is foreign matter oxidation or rust, it needs to be cleaned. If it cannot be cleaned, the damaged accessories need to be replaced. In this case, both need to be replaced. If there is noise in the handset, you can try to replace the handset to solve it.
2. There is no sound from the external speaker, that is, there is no sound when playing music, videos and ringtones. You can try to replace the speaker to solve it. Accessory replacement can only solve the fault caused by the accessories themselves.