The player four 7-digit display is inducing noise in my audio card. In attract mode, it causes a buzz each time the display flashes. Can I build a shield to prevent this? What have others done for this kind of problem?

Background:
The machine is a Bally's Fireball Classic. I've been trying to improve the sound. It works, but there is far more noise than I would like. On machine startup, there is a period of static before any sound starts. Then I get the startup sound. Then in attract mode, I get buzzing as the digit displays flash. I started by replacing the audio caps (C4, C29, C30) on the Cheap Squeak, hoping that is was a frequency filtering issue. No dice. Then I noticed the sound went away when I swung the display open. The sound clearly seems to be a function of how close the player four 7 digit display is to the audio board. I presume the digit display is inducing the static.

I hadn't thought of that. Amazon seems to have relatively inexpensive ferrite choke rings. Most are snap-on, so I shouldn't have to desolder and re-attach the connectors. I'll dive into researching this to see if it would work.

Thanks!