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Video sync issues with Tivo HD and S3

Discussion in 'TiVo Help Center' started by Jeff_W, May 4, 2012.

  1. Jeff_W

    Jeff_W Member

    45
    0
    May 21, 2005
    I live in Duvall WA. Our cable provider is Broadstripe.

    We have two cable Tivos: one is an HD and the other is an S3. On both of them we frequently see what appear to be sync issues in recordings. There will be some blocky artifacts, then the image will freeze or go black for a few seconds, and then some more blocky artifacts and then the recording will continue playing. Both Tivos get the same behavior. Generally this will happen 1-3 times during any typical one hour recording. It happens on both SD and HD channels. If it would help I could probably post a cell phone video of this.

    The cable company had a guy out a while back who said our signal strength was good and suggested that the only thing they could try is to replace our cablecards (we have two in each Tivo).

    Any other suggestions? Is there any way to diagnose what's happening and why or should I just ask Broadstripe to replace all of our cablecards?
     
  2. unitron

    unitron Active Member

    16,387
    2
    Apr 28, 2006
    semi-coastal NC
    One way to diagnose it is to also have a direct cable feed to a television so that you can see if the problem is already in the signal before it gets to the TiVos, possibly even before it gets to the cable company's head end.
     
  3. a68oliver

    a68oliver Member

    431
    0
    Jul 15, 2000
    Crawfordsvil...
    My first thought was signal level. Did the tech measure the signal right at the Tivo or earlier in the run? Have you brought up the Tivo signal strength meter and looked at it?
     
  4. Jeff_W

    Jeff_W Member

    45
    0
    May 21, 2005
    The tech measured at the box, good point. But we see this issue on both Tivos which are at opposite ends of the house. One run is quite short, the other very long, but both are equally bad.

    Just now watching live TV there was a bad "sync" episode. I flipped to diagnostics: signal stretch is bouncing between 93 and 100 with SNR of 35 dB. I noticed that the Time Since Tune Start and Time Since Signal Log were both 40 seconds (and counting up). 40 seconds in the past was about when I saw the issue.

    So, what does that mean?
     
  5. a68oliver

    a68oliver Member

    431
    0
    Jul 15, 2000
    Crawfordsvil...
    I recently had a similar episode on one of my Tivos. The pic and signal would be good on one day and bad on another, also with erratic signal levels. It also affected 3 HD channels that share the same QAM. I never have traced it down because I rarely watch those channels. Does this affect all channels or only certain ones?

    The symptons you describe could also be caused by a failing hard drive. But I thing we can safely rule that out since it affects 2 different Tivos.

    Too much signal is reported to also cause problems. Since you are hitting 100, you have no way of knowing if it is really hitting 125 or more. Also, when you say bouncing, do you mean the level changes radically over the course of a few seconds or are you talking about a slower bounce.

    I think I would try to attenuate the signal using some splitters or actual cable attenuators to see if you could get the signal down to where it is not peaking at 100.

    I also liked unitron's suggestions. I believe you can also look at corrected and uncorrected errors in the diagnostics. While I am no expert on this, I believe that if the glitches are actually embedded in the signal you receive (meaning the cable company is sending out a bad signal) you won't see uncorrected errors in the diagnostics. However, if the signal they are sending is ok and you are having reception/signal level problems, then you would see uncorrected errors.

    Hopefully, someone who understands this better than I can chime in.
     

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