I am having issues with 4 of my HD channels. Everything else seems to be fine but my HD channels 432, 434, 438 and 439 have intermittant garbling or are completely unviewable.
I have a Tivo Roamio with cablecard. I have tried swapping out the cable card to no effect. As I say, it isn't constant but it is the majority of the time. Here is an example of the diagnostics on my Tivo for one of the affected channels:
Can anyone shed any light on why I would have a few garbled HD channels on an intermittent basis? Specifically, it is four channels in close proximity to each other (432, 434, 438 and 439). I've swapped cable cards without success. Comcast is blaming the Tivo (of course) but I'm not convinced since it is an intermittent problem. Here is an example of the diagnostics screen for channel 432 at a time when the signal is garbled:
Tuner: 0 Channel 432 Frequency: 79000KHz Modulation: QAM 256 Program Number 2 Signal Source: Cable Connector Type: RF 2 Channel Bits: 3176474 Signal Strength: 98% Signal Lock: Yes Program Lock: Yes Search Complete: Yes SNR: 39dB RS Uncorrected: 137465667 RS Corrected: 393361744 RC State: Available Current Tuning Status: Tuned: Success Tune State: In progress etc.
These seem high. My 4 tuner Roamio, reset yesterday, is still reading 0 for both RS Uncorrected and RS Corrected on all 4 tuners.
Although the Tivo might be bad, it's more likely that the signal for the channel you are trying to watch is too weak or has too much noise, most often due to a poor connection between the Tivo and Comcast's network. The signal strenth (98%) and SNR ( 39dB ) you posted are good, but the high error counts suggest signal problems nevertheless.
Troubleshoot by checking all connectors and looking for damaged coax cable. Running the cable through a surge protector, a defective splitter, or too many splitters can cause signal problems as well. If there is an amplifier in the line make sure it's getting power.
If you can't find the problem, call them at the phone number on your bill or 1-800-Comcast, or chat with them using one of the "Trouble" options at https://www.comcastsupport.com/chatentry/. If they can't fix the problem remotely, 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/account/service-protection-plan/, about $6/mo). If the trouble is due to anything outside your home, you shouldn't be charged.
I've tried a variety of different configurations of splitters, attenuators and boosters without success. I have, however, found a pattern to the disruption.
I went through my entire list of channels in order to see if I could find every one that is out. I don't know if this means anything at all but here is what I found:
The following channels are so disrupted that they do not come in at all and generate V53 errors: 432 - Frequency 79000KHz 434 - Frequency 79000KHz 220 - Frequency 79000KHz 217 - Frequency 79000KHz
The following channels are very badly garbled but do not generate an error message: 439 - Frequency 85000KHz 438 - Frequency 85000KHz 201 - Frequency 85000KHz 202 - Frequency 85000KHz 203 - Frequency 85000KHz 204 - Frequency 85000KHz 205 - Frequency 85000KHz 207 - Frequency 85000KHz