cable card not receiving any encrypted channels

i have had the ceton infinitv 4 tuner for a little over a year and 2 weeks ago it just stopped working. I can get like 3 unencrypted channels and thats it. I did a diagnostics scan and opened a support ticket with ceton. they said it was probably a bad cable card and to replace it. I had two TWC techs here for over three hours, they replaced everything! new cable card,( actually they tried two different cards)  new TA  and a lot of things outside. I don't know what all, but they said everything is brand new.


the thing is everything checks out perfect. the tech says the signal is perfect and the ceton diagnostic tool reports the TA is installed, all drivers installed and service running. the cable card has received cp autorization and receiving messages. I get all green check marks in the devices and cablecard tabs  but when I try to tune an encrypted channel it says unable to aquire signal. pcr lock. I did another diagnostics scan and sent it to ceton they said the tuner appears to be working fine, but it is the only thing that has not been replaced and is about the only only thing that I can think to do. I am hoping somebody has some idea what the problem could be before I shell out the bucks for a new tuner that may  not even solve the problem.