One of the reasons which can cause a been on and beep off, especially after HDMI port replacement, can be U82, a 5-pin IC. TheCod3r has a video about it which I'll attach below. 

But, remember that you can find this IC on the original Xbox One board, model 1540.

Here is the video:

https://www.youtube.com/watch?v=mGSQIc_11gg&t=763s&ab_channel=TheCod3r