It’s a simple push-button under spring pressure normally open.
If you can find the Bottom Housing Apple P/N 076-1210 it comes with the button.
Here’s one source [https://www.dvwarehouse.com/076-1210-Apple-Bottom-Cover-for-Mac-mini-Early---Late-2006--Mid-2007-p-38585.html|Bottom Cover for Mac mini Early - Late 2006 & Mid 2007] '''It’s only $5.00 How can you go wrong!'''
+
+
If you live in the UK or EU [https://www.thebookyard.com/product.php?products_id=7945|Bottom Cover for Mac mini Early - Late 2006 & Mid 2007] It’s a bit more $25.00 ;-{ Maybe you can haggle a bit.
It’s a simple push-button under spring pressure normally open.
If you can find the Bottom Housing Apple P/N 076-1210 it comes with the button.
Here’s one source [https://www.dvwarehouse.com/076-1210-Apple-Bottom-Cover-for-Mac-mini-Early---Late-2006--Mid-2007-p-38585.html|Bottom Cover for Mac mini Early - Late 2006 & Mid 2007] '''It’s only $5.00 How can you go wrong!'''