Locking up with any cable input

Discussion in 'TiVo Series3 HDTV DVRs' started by kf6bbl, May 1, 2011.

  1. kf6bbl

    kf6bbl New Member

    May 22, 2006


    I've had this problem for a month or two that I can't figure out.
    The issue is that with the cable plugged into my Series 3, on SD channels is plays for 2 seconds then freezes for 15 seconds or so, plays, freezes, etc. On HD channels it usually shows no picture, but sometimes it will show a heavily pixelated picture. Any attempt to access the Tivo menus is extremely difficult and might take a minute to show the background screen, and the background animation is stuttering badly. After several minutes this usually ends in a self reboot.
    But if I unplug the cable signal, after a minute it will come back to life and operate as normal, just missing the cable signal. I can access all menus, stream Netflix, play Pandora, and playback recorded shows without any hint of a problem.

    Some details of fix attempts:
    Switched Digital Video - I am on Cox comm SD,CA south county system. This started about the time they switched over, so I finally just got the tuning adapter (Cisco 1520) After several weeks of trying and a couple of tech visits, it does the same thing with or without the tuning adapter. We also swapped tuning adapters, same results.
    RF Signal - signal to the tuning adapter is good (+6db), SNR is good (35). Signal to the Tivo through the tuning adapter is good (+3db).
    Signal direct cable into the Tivo bypassing the tuning adapter is good (+6db)(also had USB unplugged for this test).
    I also made sure both tuners were on lower cable channels (QAM but standard def) which are part of the basic cable tier.
    Forward/Reverse Data Dhannels - FDC signal is good ~ +3db, RDC is good, around +43db (max'ed out would be 53db, so I have plenty of headroom)
    CableCards - We swapped out both cable cards with no difference in performance.
    SA8300 HD DVR box - Also have one of these, and it has no issues from the same cable feed.
    My Tivo has no external HDD or any upgrades, bone stock.

    Whats Wrong?
    If the internal HDD was bad, would streaming and buffering Netflix work? Or playback of old shows?
    Could the QAM tuner go bad? Does that happen?
    Could there be something that Cox is sending that the Tivo does not like?

    Thanks for any help!
  2. kf6bbl

    kf6bbl New Member

    May 22, 2006
    I wiped out the Tivo with a fresh guided setup. Problem still exists.
    Is there anyone else who has a series 3 on Cox Comm SD south county?
  3. dlfl

    dlfl Cranky old novice

    Jul 6, 2006
    Dayton OH
    Which Series 3 model do you have?
    S3 (model 648)
    HD (model 652)
    HD XL (model 658)
    How old is it?
    How are you measuring a 6 dB signal into the TiVo when bypassing the TA? AFAIK, the TiVo only measures signal on a 0-100 scale.

    If you go into DVR Diagnostics what are the signal strengths for the two tuners (on the 0-100 scale)? Pick any 1 or 2 channels you can tune for this.

    Also the Cisco TA amplifies the signal 2 or 3 dB so it doesn't make sense you are getting 3 dB out (to the Tivo) with 6 dB in (from the cable).

    There have been quality problems with the short coax cable that comes in the TA kit. Ask ComCast to replace that on the next truck roll, if not done already.
  4. markens

    markens Member

    Apr 12, 2007
    This sounds very similar to lockup problems discussed at length in this thread.

    To summarize the referenced thread: The most commonly accepted theory (in this forum, anyway) is that the described problem is due to a failing hard disk that cannot handle the write load of HD signals. The 30 minute buffers (one for each tuner) are being written whether they're being "recorded" or not. This explains why the freezing behavior stops when input coax is removed. And playback is not affected.

    That it happens on SD signals as well (although to a lesser extent) is a wildcard here.
  5. kf6bbl

    kf6bbl New Member

    May 22, 2006


    Model 648

    I bought it last fall as a factory refurbished unit.

    You are correct. I think I had mixed up that with what I was reading from my SA8300 box. The Tivo reports SigStrength of 95 for both tuner 0 and tuner 1.

    That was the first thing I asked to be replaced, which they did and no better results.

    I called Tivo yesterday and they had no better diagnosis, but they can replace it for $49. I'm weighing my options at this point because it's all making less and less sense to continue. One of my thoughts is to dump cable all together, and put this Tivo on an antenna just to get a few shows the wife wants. Everything else we can get from the internet. Which gives me a good troubleshooting idea. I'm going to put an antenna on this thing to see if it works. BRB...
  6. kf6bbl

    kf6bbl New Member

    May 22, 2006
    Went through the guided setup again to set it or antenna input only, and pretty much the same results. I made an improvised antenna and was able to get a max signal strength of about 80, but how it behaved was the same as the cable input. The picture stutters, slow or no response to remote button presses, and eventual reboot.

    So I think I can make the conclusion that it's not Cox cable, and that there is something wrong with this Tivo. Either the HDD as was suggested or something in the RF tuner hardware.

    I've already been planning on putting in some sort of media center PC or Mac, and for the same $49 I can attach an external HD tuner, and I wouldn't need to pay Tivo $12.99/month.
    I think this is going to put me out of the Tivo game, so after 12 years and 4 Tivos, Good Night!

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