Hauppauge PVR 250 upgrade to 1600 ?

[Crowdx42]

Hi all,
been a long time since I have posted but now I have a question. I currently have 3 PVR 250 tuner cards and now with everything going digital I am wondering how this will affect me.
Currently all the cards record directly from the coax coming into the house. We just upgraded our Comcast back to the digital service but the PVR 250 does not seem to be able to tune the channels when I select Digital in the sage tv guide.
Is it a limitation of the PVR 250, would a 1600 work for this or is it now impossible with digital cable to record any of the extra channels.
I am in the Bay Area in California and I am now wondering if digital is not compatible with tuners due to some encryption or the like, is Sage worth messing with due to then needing multiple tuner boxes to record from them to Sage via composite out.
All advice welcome, very rusty on what is currently going on.