I've had this problem for a month or two that I can't figure out. The issue is that with the cable plugged into my Series 3, on SD channels is plays for 2 seconds then freezes for 15 seconds or so, plays, freezes, etc. On HD channels it usually shows no picture, but sometimes it will show a heavily pixelated picture. Any attempt to access the Tivo menus is extremely difficult and might take a minute to show the background screen, and the background animation is stuttering badly. After several minutes this usually ends in a self reboot. But if I unplug the cable signal, after a minute it will come back to life and operate as normal, just missing the cable signal. I can access all menus, stream Netflix, play Pandora, and playback recorded shows without any hint of a problem. Some details of fix attempts: Switched Digital Video - I am on Cox comm SD,CA south county system. This started about the time they switched over, so I finally just got the tuning adapter (Cisco 1520) After several weeks of trying and a couple of tech visits, it does the same thing with or without the tuning adapter. We also swapped tuning adapters, same results. RF Signal - signal to the tuning adapter is good (+6db), SNR is good (35). Signal to the Tivo through the tuning adapter is good (+3db). Signal direct cable into the Tivo bypassing the tuning adapter is good (+6db)(also had USB unplugged for this test). I also made sure both tuners were on lower cable channels (QAM but standard def) which are part of the basic cable tier. Forward/Reverse Data Dhannels - FDC signal is good ~ +3db, RDC is good, around +43db (max'ed out would be 53db, so I have plenty of headroom) CableCards - We swapped out both cable cards with no difference in performance. SA8300 HD DVR box - Also have one of these, and it has no issues from the same cable feed. My Tivo has no external HDD or any upgrades, bone stock. Whats Wrong? If the internal HDD was bad, would streaming and buffering Netflix work? Or playback of old shows? Could the QAM tuner go bad? Does that happen? Could there be something that Cox is sending that the Tivo does not like? Thanks for any help!