Sound on NBC feeds to KFOR

[USG '60]

I have and old fashion TV and use a converter box. For the last 3 days the sound is nearly nonexistant on the NBC News, The Tonight Show and Saturday Night Live. The laugh tracks and sound effects come through loud and clear on the comedies but the main mike is nearly totally dead. I have never heard of such a thing. Is it NBC, KFOR, my TV, my converter box or a strange combination of them. Can anyone offer any help on this?

[USG '60]

Never mind. It fixed itself last night.