Cox Cable, Gainesville Florida, TiVo HD I think (it's at my mom's house right now), newly brought back up after spending some time offline, freshly installed and paired CableCard. Works like a charm, just like it did when I had it up and running many moons ago when I had the same cable service, except...
The current subscription package includes a tier of channels called the Variety pack. Some of those channels (4 I believe) do not come up when tuned to. They have listings in the Guide data, but tuning to them will either show a black screen, or sometimes show the TiVo message that Channel Not Available.
We swapped out CableCards and re-paired, and the same channels have the same problem. The Signal Strength screen and DVR Diagnostics screen show 100 signal strength almost all of the time. I vaguely remembered the signal being too strong sometimes causing problems with TiVo, so I put some attenuators inline (up to 24db at one point) until the numbers came down from 100 to no avail.
And herein lies the tricky part. When I force the tuner to one of the "bad" channels, and go to the DVR Diagnostic screen, most of the information is empty and there's a strange looking text blurb in one of the data spots that reads like "Card / tuner in invalid state" or something to that effect (again, sorry I didn't write more of this down...obviously if asked I can gather necessary information and post it.) If I bring up the Signal Strength overlay, it will not tune to that channel at all; the channel up/down skips past it, and typing in the number jumps to the next channel in the lineup.
When the "bad" channel displays "Channel not available" I cannot record it. When it's a black screen, I can record it, but playing the recording back later indicates it actually recorded the previous channel in the lineup.
She had a Cox subcontractor out, (I was not there at the time, this is second-hand knowledge) but supposedly used his smartphone to measure the lines and he seemed to say the line leading to this outlet was too weak (which goes against what the TiVo is saying but I'm no expert.) She called Cox and told them all the stuff he did / didn't do and they seemed to think he was an idiot and will send out a Cox employee next to see if he can figure it out. I imagine a call to TiVo is next, but I need to look up their support policies as this one is several years old.
I figured I'd troubleshoot in parallel here in case this is a common issue that people know what the problem is. My next step is to move the TiVo to another room temporarily to see what happens and if anything is different, just to rule out what the sub said.
Open to suggestions...