reply to neufuse
Re: CCs losing authorization in TiVo S3 Or sometimes not - as multiple techs have posted, new cards often don't work. But again my bet is that most of them were provisioned wrong in Comcast's system, like setting them up for two-way devices (Comcast's stuff) when they need to be one-way (Tivo, PC tuners, etc.).
We're way past the time where 3rd party devices are the issue - modern Tivos and PC tuners handle cards just fine, so it's almost always the provider's fault now when it happens.