如何修改apt源？

[niclau]

设备：N1
OS：Armbian_23.05.0_amlogic_s905d_jammy_5.15.110_server_2023.05.13.img
我没有修改过apt源，现在设备不在中国网络环境了，但apt update时仍会出现中国的源地址，如http://mirrors.tuna.tsinghua.edu.cn/armbian ，该如何让apt重新识别网络环境，使用当地的源？

$ sudo apt update
[sudo] password for niclau: 
Hit:1 https://download.docker.com/linux/ubuntu jammy InRelease
Hit:2 http://ports.ubuntu.com jammy InRelease                                                                                                            
Hit:4 https://pkg.cloudflare.com/cloudflared jammy InRelease                                                             
Hit:5 http://ports.ubuntu.com jammy-security InRelease
Get:6 https://pkgs.tailscale.com/stable/ubuntu jammy InRelease                            
Hit:3 http://mirrors.tuna.tsinghua.edu.cn/armbian jammy InRelease                         
Hit:7 http://ports.ubuntu.com jammy-updates InRelease
Hit:8 http://ports.ubuntu.com jammy-backports InRelease
Fetched 6,522 B in 3s (2,215 B/s)
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
65 packages can be upgraded. Run 'apt list --upgradable' to see them.

[mengzai-c]

你试试在armbian-config里改一下时区试试