Worked Great - Now no Digital Channels

Discussion in 'TiVo Help Center' started by TivoFan, May 27, 2011.

  1. TivoFan

    TivoFan New Member

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    Feb 22, 2000
    Northampton, MA
    I'm having a problem receiving the digital channels on my Tivo and I'm trying to figure out what is wrong. Let me preface everything else by saying that the Tivo has been set up, working great and had no problems since we've moved to our new house 8 months ago. We haven't changed anything so I don't know what caused the loss of channels.

    I have a Tivo Series 2 Dual Tuner and comcast cable. Because of the cable service I originally had to set up the Tivo with a coaxial cable coming in for one tuner as well as an s-video cable for the other. One of those carries the digital stations and the other carries the other carries the analog stations. The coaxial cable comes from the wall, is split and one cable goes directly to the Tivo and the other goes to a small device from the cable company. The S-video cable comes out from the device into the Tivo. This setup has been working for the past eight months, so I know there isn't a problem with that.

    I still get all the analog stations, but when I try to change the channel to one of the digital stations all I get is a black screen and a Tivo message "Searching for Signal on: basic cable in"

    I'm trying to figure out what the problem might be. Any suggestion would be appreicated.
     
  2. That Don Guy

    That Don Guy Now with more GB

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    Benicia, CA
    I can think of three possibilities:
    1. The cable between the splitter and the "cable company device" is bad/loose.
    2. The S-video cable is now bad/loose.
    3. The cable company's device suddenly went bad.

    Does your TV have an S-video input? If it does, try disconnecting the S-video cable from the TiVo and plugging it into the TV, and see if you get a signal there.

    -- Don
     
  3. scandia101

    scandia101 Just the facts ma'am

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    MN, greater...
    Reboot the cable box
     
  4. Jul 2, 2011 #4 of 12
    TivoFan

    TivoFan New Member

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    Northampton, MA
    I was out of town and did not have a chance to try your suggestion yet. I just did that this morning. When I take the S-video cable that goes into the Tivo and plug it directly into the TV, I am able to get full cable signals through the TV.

    This makes me think that the problem must be with the Tivo and probably with the second tuner? Does that make sense?

    What would I need to do to fix this?
     
  5. Jul 2, 2011 #5 of 12
    unitron

    unitron Well-Known Member

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    Technically, the second tuner isn't involved since you're recording the input to the audio jacks and the S-Video jack, although the software that handles the whole "use the second tuner or the line inputs, depending" situation may be having problems.

    Find an old VCR or something that can run into the audio and composite video (yellow jack) inputs, and see if you can record anything that way.

    If so, then the S-Video input circuitry itself has gone bad.

    If not, it may be a software problem.

    Does the cable box have any outupts besides the S-video (and, I assume, white and red audio jacks)?
     
  6. Jul 2, 2011 #6 of 12
    TivoFan

    TivoFan New Member

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    Northampton, MA
    I went and got our other Tivo from the other room and set it up. I connected the s-video cable from the cable box into it and it worked.

    So the s-video output from the cable boxes works when plugged directly into the TV and into our second Tivo, but not when plugged into our main Tivo.

    So what is the problem with the the main Tivo?


    And the cable box only has a coaxial out and the S-video out (with the red and white audio outs).
     
  7. Jul 2, 2011 #7 of 12
    unitron

    unitron Well-Known Member

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    Co-axial out meaning imitation analog channel 3 or channel 4? Silver metal threaded thingie, no yellow RCA jack anywhere?

    How does the TiVo tell the cable box to change channels?

    (if all else fails, there's some surgery that can be done to allow accessing the two tuners co-axial inputs separately, although if it's not a lifetimed box it might be simpler to pick up another of the same model off of Craigslist for $20)

    Perhaps the troublesome TiVo has just gotten confused.

    You could try re-running Guided Setup, telling it a different configuration, and then re-run it again telling it the truth and see if it resets.

    You could also try other TiVo red, white, yellow (stored program playback) into troubled TiVo input jacks (nothing plugged into S-video jacks on either machine) and see if you get picture and sound that way, in which case suspect S-video input circuitry.
     
  8. Jul 2, 2011 #8 of 12
    TivoFan

    TivoFan New Member

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    Feb 22, 2000
    Northampton, MA
    Coaxial cable is what appears to be a copper wire surrounded by white insulator and covered in a black rubbery outer sheath. The typical cable that comes out of the wall and plugs into your cable box.


    For the digital channels I'm using an IR blaster to control the cable box to turn the channels. My understanding is that for the basic channels on the coaxial cable all the channels are coming through and Tivo just has to pick one out.

    What? I don't understand what you mean.
     
  9. Jul 2, 2011 #9 of 12
    unitron

    unitron Well-Known Member

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    Use your TiVo that's not giving problems as a known good audio/video source.

    Get one of those cables with red, white, and yellow RCA plugs at both ends (look in one of your old TiVo boxes), or the electrical equivalent, they can all be the same color or any color, but you want to go from good TiVo composite video out (yellow jack) to problem Tivo composite video in, and the same for the audio.

    Have no S-video cables attached to either machine.

    Play back a recording on the good Tivo, say a one hour one.

    Tell the problem Tivo to record a show (maybe a half hour one) from the cable box (which won't actually be attached to anything at this point, but while we're at it, check to make sure that the TiVo actually gets it to change channels).

    See if the problem Tivo actually recorded what the good Tivo was feeding it.

    If so, the problem isn't the TiVo software, it's the problem TiVo's S-video input and/or the associated circuitry, including possibly whatever it uses to detect the presence of an S-video cable/signal.
     
  10. TivoFan

    TivoFan New Member

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    Feb 22, 2000
    Northampton, MA
    I must be using the wrong terminology then. I thought the cable with the white red and yellow connectors was the S-video cable.

    That is what I've been using to connect from the cable box to the Tivo.
     
  11. unitron

    unitron Well-Known Member

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    On the back of the TiVo, to the right, if viewing the back of the TiVo, of the audio/video inputs and outputs are black plastic jacks with 4 round holes (that are for luminence and its ground, and chrominance and its ground) and smaller and larger rectangular holes at top and bottom, which are not electrical but help with aligning the plug with the jack. They look similar to PS/2 mouse and keyboard jacks (but the pin placement is incompatible, as are the electrical signals).

    Those are the S-video jacks. They get used instead of the yellow jack if you do an S-video hookup. (supposedly the video is better that way) The left and right audio (white and red) still get used for the audio.

    So, now that we've established that your cable box outputs composite video (its "composed" of the luminance and chrominance signals joined together as one signal that has to be unjoined by circuitry in the TiVo or TV) and 2-channel stereo audio, and/or an RF signal from the silver threaded thingie (which joins the composite video and the audio into one signal that rides on a channel 3 or 4 carrier), and apparently does not have an S-video output, we have to figure out a new way to approach troubleshooting.

    Go ahead and do the "good TiVo as a red, white, yellow source" experiment anyway, and let me know if it gets recorded (and if the cable box changes channels like the TiVo tells it to) while I try to brainstorm something else to try.

    And dig through your old TiVo boxes and see if there isn't an S-video cable (it'll be black) in one of them.

    After you do the above experiment, do it again with the S-video cable running between the good Tivo's output and the problem TiVo's input, with the yellow plug cable disconnected on both ends, but the red and white still hooked up.
     
  12. ggieseke

    ggieseke Well-Known Member

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    Check your Video settings on the TiVo. You can switch between composite and s-video without running the entire Guided Setup. If it's set to s-video and you're using composite (or the other way around) it would cause your problems.

    It's also possible that the yellow RCA jack for composite has broken loose from the motherboard, especially if you use Monster brand cables. A little soldering sould fix that, or you could just switch to s-video. Most local stores charge a fortune for s-video cables, but monoprice.com is cheap.

    P.S. I can see a definite improvement in picture quality using s-video, but you have to use it from the cable box to the TiVo AND from the TiVo to the TV. My TV is a 36" Sony Vega with an incredible picture, so YMMV.
     

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