My Series 3 Keeps Pixelating

Discussion in 'TiVo Series3 HDTV DVRs' started by BeanMeScot, Sep 6, 2009.

  1. Sep 6, 2009 #1 of 18
    BeanMeScot

    BeanMeScot Sci-Fi Junkie

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    For the past few weeks, every time I watch my series 3 for couple of hours or more, the picture starts pixelating. It doesn't happen when I first turn it on. It will get worse and worse until it loses the signal completely and I get the searching for signal message. I can change to the other tuner and it is usually better. I can stay on the other tuner for a while, then it starts pixelating, too. Then I can go back to the other tuner and it is now ok. Back and forth. The picture is beautiful when it is up. Then both tuners will be fine for a while.

    Comcast sent some kind of signal to the modem but it is still happening. I had Comcast out here last week and the signal to the TV was fine. He changed the connector outside. But it is doing it again today. Today is the first time I have watched it a lot since Comcast came out. I have rerun the guided set up and that didn't fix it either.

    The Tivo has not been hacked and does have the extended hard drive. The 500gb made for the Tivo.
     
  2. Sep 6, 2009 #2 of 18
    dlfl

    dlfl Cranky old novice

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    When you say "turn it on", you mean your TV right -- not the TiVo, which is running constantly. (?)

    The behavior you describe suggests something is heating up and failing. That's what makes your problem really puzzling to me. AFAIK everything in the TiVo normally is running all the time. (Tuners are tuning, disk drive is writing and reading, etc.) So what could be getting hotter when you "turn it on" or change tuners?

    What does Internal Temperature say in Messages & Settings ==> Account & System Information ==> System Information (3rd page on my THD) ?
     
  3. Sep 7, 2009 #3 of 18
    bkdtv

    bkdtv New Member

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    When tuned to these pixelizating channels, do you see millions of RS Uncorrected errors on the DVR Diagnostics screen under Messages & Settings -> System Information? If so, then you have a signal issue, which could be caused by a defective splitter or cable.

    If you see this pixelization with few or no RS Uncorrected errors, then chances are good that a problem with the internal or external hard drive. In the overwhelming majority of cases, the culprit is the external hard drive or its eSATA cable. The disk errors caused by a failing external hard drive, defective eSATA cable, or loose eSATA connection tend to be most noticable on HD channels. To confirm this as the culprit, disconnect (unmarry) your external drive; be aware you will loose any recordings made since the external drive was added.
     
  4. Sep 7, 2009 #4 of 18
    BeanMeScot

    BeanMeScot Sci-Fi Junkie

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    Yes. The Tivo runs constantly but I am turning the TV on.

    It says Normal 47 Ceclius
     
  5. Sep 7, 2009 #5 of 18
    BeanMeScot

    BeanMeScot Sci-Fi Junkie

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    In looking at it yesterday and today, I think it is doing it on certain channels. I keep it on the HD channels like Discovery, Science, History, etc. Those are the ones that keep pixelating. Yesterday I kept it on the Food Network and HGTV and it had no problems. Today I put it on Science Channel for about an hour and lost the channel.
     
  6. Sep 7, 2009 #6 of 18
    dlfl

    dlfl Cranky old novice

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    Checking the RS Uncorrected error counts as bkdtv suggested is a good thing to do, although I'm still baffled by why this only occurs after a period of time viewing one tuner, rather than all the time.

    bkdtv, is there some circuitry that actually only is active when you are using a particular tuner, and could heat up depending on length of tune time? That still wouldn't explain a delay after turning on the TV, unless the OP typically switches tuners at the same time.

    The 47C temp is in the normal range, I believe (in fact it should say "normal" right after the temp reading).
     
  7. Sep 7, 2009 #7 of 18
    dwgsp

    dwgsp Member

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    Do you have a tuning adapter? If so, is it getting hot, which might cause problems tuning SDV channels.

    /Don
     
  8. Sep 7, 2009 #8 of 18
    BeanMeScot

    BeanMeScot Sci-Fi Junkie

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    What is a tuning adapter?

    Yes, the temp is normal.

    I have pixelation on Science channel right now. On Cablecard 1:Uncorrected RS is 400k and going up. Corrected is over 10 million. Signal strength is 40. After a couple of minutes, RS is now almost 600k and corrected is 13 million. Cablecard 2: signal 81 uncorrected 3k, corrected 7500.

    After coming back to Cablecard 1, the RS is still going up. Over 900k uncorrected and 20 million corrected.

    What does RS mean?
     
  9. Sep 7, 2009 #9 of 18
    BeanMeScot

    BeanMeScot Sci-Fi Junkie

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    Going back to Live TV, the picture now looks fine but I am getting signal of 42 and RS uncorrected over 1 million and uncorrected over 23 million. The uncorrected is staying at exactly the same number now; 1,073,319. The corected is continuing to go up.
     
  10. bkdtv

    bkdtv New Member

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    A tuning adapter is what is used for SDV channels. It's also referred to as a "SDV adapter" or "SDV dongle."

    RS (Reed-Soloman) Uncorrected errors are signal errors that cause pixelization and audio dropouts. They can be caused by a defective connector, defective or ripped cabling (ex: squirrel chewed through cable), and/or an insufficient signal level. In your case, it sounds like the signal level is to blame. For a stable picture, you need a signal in the mid 60s, and a signal of 80 or higher is greatly preferred.

    Signal strength across all frequencies is not linear, so some variation in signal level from channel to channel is normal. You might have some channels at 90 and others at 80 (or some at 70 and others in the 60s). If you see more substantial variations, such as a difference of 20-30 between channels, then that suggests a defective connection (or splitter) or cabling.

    Based on the information provided, you need to have your cable company out to check your cable or connections. Something is causing an abnormally low signal level, and that causes pixelization. You've got a barely adequate signal, so environmental / RF conditions (both inside and outside the home) cause your signal to drop in and out of an acceptable range.
     
  11. dlfl

    dlfl Cranky old novice

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    Your Uncorrected Error counts are way too high and your signal level is very low (40), which is most likely what is causing the errors.

    You didn't by chance read the SNR number instead of Signal Strength did you? The typical SNR range is 32 to 36.

    The desirable range for signal strength is 80 to 99.

    RS is for Reed-Solomon, which is the algorithm used for the error correction. Why someone thought displaying the "RS" helped anyone is beyond me.

    The low signal strength can be caused by cabling or splitters in your domicile, or it could be low coming from the Cable Co. The cable co. can check this out.

    One question is what the signal strength is doing over all channels. Ideally you want to get it in the 80-99 range for all channels, and it may vary over channels. I have to let some channels go to 100 (which probably means more than 100 since that's the upper limit) in order to get others above 80. For me that is the best compromise but YMMV.
     
  12. BeanMeScot

    BeanMeScot Sci-Fi Junkie

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    I have one cable going into the Tivo. How can channels have different signal strengths and the cable cards have different signal strengths when it all comes from one cable? The cable guy did check the signal strength from the cable when he was here and it was fine. Also, why would this suddenly become a problem? I have had cable hooked up for over a year and this started in the past 3 weeks or so.

    FYI, the SNR is at 27
     
  13. dlfl

    dlfl Cranky old novice

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    Did the cable guy check the signal right where it goes into your TiVo, or where it enters the premises? If it was the latter, then probably something between the entry point and your TiVo is the problem.

    It is not unusual for signal strength to vary with channels. Each channel is a different frequency, and both attenuation and the strength coming from the cable co can vary with frequency.

    Your SNR is very low, consistent with low signal strength.

    As a sanity check, look at the same channel's signal strength on both tuners. If it varies more than 1 or 2 there may be something wrong with one tuner. But this may be hard to do if the signal is fluctuating.

    If you get the same low reading for a given channel on both tuners, it has to be weak signal -- regardless of what the cable guy measured. If this just started happening after he measured it, then you can logically request another test, since something has changed.
     
  14. BeanMeScot

    BeanMeScot Sci-Fi Junkie

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    He unhooked it from the Tivo and then checked that end. He also said he changed the connector outside. So I would say he checked it at both points.

    How can you get both tuners on the same channel? When I try, it just changes to the other tuner since it is already on that channel.
     
  15. bkdtv

    bkdtv New Member

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    You don't have to tune the channel at the same time. You can check the channel on one tuner, change the channel, and then press the LiveTV button to switch to the other tuner.

    A small difference between the two tuners is normal.

    As I indicated above, different channels are on different frequencies. Signal strength won't be linear on all frequencies from 0-860MHz, due to cable loss and RF interference, which do not affect all frequencies equally. That said, you should generally see no more than +/- 10 variance in TiVo signal strength (or +/- 2 in SNR) unless there is a defective coax, connection, or splitter. Variance is fine so long as your signal never falls below the mid 60s.

    A SNR of 27 is too low.

    Some animal (squirrel) or bird (woodpecker) could've ripped into your coax. If the installer didn't use weatherproof connections, and you've recently had a lot of rain, that could also be the culprit. Another possibility is that your connections inside or outside came lose.
     
  16. BeanMeScot

    BeanMeScot Sci-Fi Junkie

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    I've called Comcast and they will be coming out tomorrow. We will see what they do this time. Thanks!
     
  17. BeanMeScot

    BeanMeScot Sci-Fi Junkie

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    Comcast is now saying the signal is weak but it is weak coming in from the street so they are going to have an engineer come by and see what they can do to get a better signal from the street.
     
  18. dlfl

    dlfl Cranky old novice

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    :up:
     

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