I own 2 Series 3 Tivos. About every 6 to 9 months one or both of the Tivos begins constant rebooting. If I pull both cablecards, the Tivo will complete the reboot. I can then test the cablecards by plugging them back in one at a time. Usually plugging one (or both) cards into slot 1 will cause a reboot. In the past, it usually took 2 trips by the cable tech and about a dozen cablecards to find a pair of cards that will not cause the Tivo to reboot. About 4 weeks ago, one of the Tivos began rebooting. I pulled the cablecards and the Tivo rebooted, and I could access all prior recordings. I found one of the cards caused a reboot if placed into slot 1. A few days later the tech came out with 6 used cards. All of them caused a reboot as soon as placed into slot 1. I was left with one of the original cablecards which allowed one tuner in slot 1. Two weeks later, the Tivo began rebooting again with this one card in slot 1. Tuesday night, the tech brought out 12 cards. For 2 hours we tried cards. We found several that worked in slot 1, but placing one of these into slot 2 caused a reboot (working card was in slot 1). We finally gave up, as several cards were marked bad, and Tivo provides no diagnostics of the failure mode. I was again left with one tuner. Last night (Wednesday) the Tivo again began continuous rebooting. Pulling the "new" cablecard solved the reboots. Charter is saying the Tivo is bad. Tivo is saying the cablecards are bad. I tend to believe Tivo, as this problem has been happening on 2 Tivos over the last 3 years. It used to be easier finding a good pair of cablecards when Charter carried new cards--they no longer will provide new cards. But, both Tivos have always been very sensitive to the particular pair of cards installed. It seems like there is a minor incompatibility between Series 3 Tivos and certain cablecards. Before scrapping 2 Series 3 Tivos ($1500 worth of equipment), one with Lifetime Service, I was wondering if anyone else is having a similar problem, and if there is any solution. Tivo's solution is of course to buy all new equipment, which is unacceptable for 3 year old equipment. Based on some inquiries, it also seems that Series 3 Tivos can not be repaired. So, unless I can get this fixed, I will need to find a cheaper (and less better) alternative to Tivo.