Help with Arthur Harrison's 1999 Minimum Theremin Design

Hi everyone!

For the past month, I've been attempting to build Arthur's Harrison's 1999 theremin design as part of a class project. I got it to work a week ago — I could hear very faint whistling sounds produced from the speaker. But all of a sudden, it stopped working, and all I hear now is a loud and flat buzzing sound that doesn't change pitch/volume when I move my hand around the antenna. 

I put some photos and videos of the circuit on this google drive link here: https://drive.google.com/drive/u/0/folders/16Vfz7S86OhSJukf36V2oXo4Oq1Gn9Cje

I'm relatively new to electronics, so any advice or suggestions would be appreciated! 

Cheers, 
-Chloe 

Hi Chloe,

It looks like you're running your antenna wire right under your audio cable?  I would keep them separate, that wire is just as sensitive as the antenna.  I couldn't quite see, but it seems you have a scope on your bench?  If so, I'd start by probing all of the oscillators to see if they are functioning.

If it suddenly stopped working, there is a chance that ESD damaged the IC.