About a week ago my Series 2 started having a high pitched whining sound being recorded along with the program's audio. It makes the program's audio very hard to hear. If I watch older TiVo recordings, the audio sounds fine. Audio straight through the TV is also fine. Seems like something broke about a week ago...

Any idea what it could be? Does it need to go back to TiVo for a motherboard repair? I've got lifetime on the unit, so I don't really want to replace it.

Thanks,
Bob