After doing a quick google search, you can find the motherboard part on https://notebookparts.com/products/new-genuine-lenovo-ideapad-1-15iau7-82qd-motherboard-win-pentium-u15-4g-5b21h70593 . [br]
Note: this links to an external site. I have visited it myself but cannot completely confirm its legitimacy, and it is recommended to do research on any external links given over the internet.