Sorry I tried alt.audio.equipment with no luck.

I have a Kloss model 88 radio connected to a nearby PC that has one of
those Win/TV cards. I wired the audio out of the TV card to the CD
inputs of the radio. The CD inputs are RCA jacks.

The setup works OK, but every once in a while the radio starts
"booming". By this I mean it sounds like the bass was turned way up.
If I touch or jiggle the back connection the booming goes away. The
same thing happens if I use the stereo plug AUX input.

What's happening here and how do I stop it?

(PS. The radio does not have separate a grounding connection.)

--zeb