I have a sorta strange problem. I'm a new Comcast customer and have a CableCard in a refurbished Tivo XL4. The card seemed to activate fine and I can receive nearly all the channels I should receive EXCEPT 7. Those 7 are all "local" HD channels, and the numbers are near each other but not contiguous. I can receive the SD versions of those 7 channels, so it's not an emergency.
Someone on a Tivo forum suggested I use the Tivo diagnostics to look at those channels, and it seems all 7 are subchannels of the same frequency (309000). Someone else suggested that the CableCard does not know one frequency from another, so it might not be the card. I have an X1 box too, and it receives those 7 channels fine. Does anyone have any ideas? Thank you very much.
Thank you, Brucew, there's usually a v52, and the diagnostics show a very low signal (probably just noise) on those 7 channels (the diagnostics show all 7 are subchannels of 309000). The Tivo how-to seems to be more for overall problems, but everything is fine except for those 7 channels (signal strength is in the 80s). The problem seems to be just that one cable frequency (309000), and only in the Tivo - the XG1 hung off the same splitter gets those 7 channels fine.
I can probably live with the problem, since the SD versions of those 7 channels work fine. I actually tried to get a swap for the card, but although the service center had 5 cards, they couldn't give any to me because they were somehow not correctly added to their inventory. I took this as an omen
@LarryR2 wrote: ... there's usually a v52, and the diagnostics show a very low signal ...
V52 is a No Signal error. That suggests that there's a splitter or coax cable problem or, less likely, a faulty Tivo tuner. The information for splitter/coax problems in modem Connection Troubleshooting Tips might help you.
If you can't find the problem or you'd rather have Comcast take care of it, call them at the phone number on your bill or 1-800-Comcast, or use one of the options on https://www.xfinity.com/support/contact-us/. If they can't fix the problem remotely (unlikely), insist they send a tech out to identify the cause and correct it.
If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast originally supplied them) you'll probably have to pay for the visit unless you have their Service Protection Plan (https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device, or anything outside your home, you shouldn't be charged.
... I actually tried to get a swap for the card ...
Cablecards decrypt and authorize channels, but they don't tune them, so I doubt a card swap would help. A Cablecard error should produce a different error code, probably V58.
Thanks again, BruceW. I agree with your analysis, but everything works fine except those 7 channels, so I can't see how it's coax or splitters. The signal strength is fine for the 300+ channels that do work. The Tivo and XG1 are attached to the same splitter, so that would have to be a pretty smart splitter to send all but one frequency to only one of the ports.
Is there a chance it's a channel mapping problem, where those 7 channels are being mapped to the wrong cable frequency? Is there a way to identify the frequency/subchannel of a broadcast channel on the XG1 to see if it's different?
@LarryR2 wrote: ... everything works fine except those 7 channels, so I can't see how it's coax or splitters ...
It sounds odd, but it's entirely possible.
... Is there a chance it's a channel mapping problem, where those 7 channels are being mapped to the wrong cable frequency? ...
It's unlikely. If that happened, the XG1 wouldn't be able to tune them either.*
* ETA: I'm assuming here that the Cablecards in both devices are receiving
the same channel map. that assumption may not be correct.
Oh. I thought a separate channel mapping table is loaded onto the CableCard so the Tivo knows where to look for a particular channel number. The Tivo channels list looks fine (from the guide source).