Skipping Sound

Welcome everyone.

I have Tivo Series 2 which started having strange problem. From time to time the sound starts skipping like on scratched CD. It happens on all channels and also while in the menu. It will last from few minutes to couple of hours. It can start anytime. Rebooting, unpluging the power cord or restarting doesn't do anything. While the problem is present, it also affects the previously recorded shows.

Any ideas?

Thanks in advance....