Troubleshooting broken audio on a CRT
I've had a simple stereo setup in place with my late 90s-ish JVC CRT for over a year now. I picked up a pair of cheap speakers at a thrift store, wired them up, and I've been using them somewhat frequently without any problems until now. Yesterday they started cutting out or crackling at intervals. They'll work perfectly fine one moment, then the audio will get quiet or choppy the next.
My first thought is that something was wrong with the speakers so I picked up a "new" pair at the thrift store and replaced the existing ones only to run into the same problem. I've also tried two different input devices to similar results, so I don't think the source of the audio is the problem. Is there a way to troubleshoot what might be wrong with my setup? Feel free to steer me elsewhere if this is the wrong subreddit for this sort of question.