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Good cable signal, but gray screen

Discussion in 'TiVo Help Center' started by dolphin, Oct 1, 2013.

  1. dolphin

    dolphin New Member

    74
    0
    Dec 3, 2007
    My TivoHD is showing only gray/white screen output when on live TV. It is not recording anything as well. It's almost like it is not connected to the cable input. But, using Settings>Cable>Signal Strength shows that there is plenty of input strength, typically 95+.

    Now Playing is fine, so Tivo does output (HDMI) to the screen.

    I've tried a power cycle a couple of times. I've tried pulling and reseating the m-cablecard. My cable line comes in to the house, splits to two. The other line is connected to a same-model TivoHD and it is doing just fine.

    Any suggestions to look for in debug??
     
  2. unitron

    unitron Active Member

    16,387
    2
    Apr 28, 2006
    semi-coastal NC
    Look at the DVR diagnostics (or something like that) that shows what each tuner is trying to tune to, which frequency, what modulation scheme, etc., and it also shows what's going on with the cable cards if you have them.
     
  3. dolphin

    dolphin New Member

    74
    0
    Dec 3, 2007
    The DVR diagnostics from working to non-working TiVo units appear to be the same, EXCEPT for two line items called "RS Connected" and "RS Unconnected". For the working unit, these stay at "0" quite a bit and occassionally increment up, adding a 100 or so. The non-working unit on the other hand, is at tens of thousands.

    No idea what RS connected is.

    Any ideas?
     
  4. unitron

    unitron Active Member

    16,387
    2
    Apr 28, 2006
    semi-coastal NC
    I'm pretty sure it's "corrected", and not "connected".

    Well, the RS is Reed–Solomon

    (that's 2 separate guys, not uconn math professor Reed Solomon )

    http://en.wikipedia.org/wiki/Reed–Solomon_error_correction

    Here's a TCF'er's take on it:

    http://www.tivocommunity.com/tivo-vb/showthread.php?p=7462618#post7462618


    and here's a thread with a good explanation about 4 or 5 comments down:

    http://www.tivocommunity.com/tivo-vb/showthread.php?t=370374

    Personally, I think the HDs have an unadmitted cable tuner demodulating and processing problem.
     
  5. dolphin

    dolphin New Member

    74
    0
    Dec 3, 2007
    Yes, you are right. Is corrected and uncorrected. I stand corrected.

    So I read the other TCF posts that you recommended, and reviewed the DVR diagnostics.

    On the good DVR, I have SNR=35, and the occasional uncorrected.

    On the non-working DVR, when tuned to lower channels (2-28 or so), the signal strength ranges from 0-50, with SNR= about 28. Lots of uncorrected. That tells me that there is a problem.

    Then, I set one tuner at channel 44 and another at channel 43. Signal strength in the mid-90s for both. SNR=35 solid. No uncorrected (i.e., =0).

    So, for the non-working DVR, I would expect those upper channels to be OK. just not the lower channels.

    I suppose the next thing to do is to physically swap the DVRs. Then, I should be able to figure out if it is the hardware or the coax.
     
  6. dlfl

    dlfl Cranky old novice

    6,997
    17
    Jul 6, 2006
    Near...
    In DVR Diagnostics what do the "gray" channels have for:
    Signal Lock
    Program Lock
    PCR PID
    Audio PID
    Video PID

    You should have "Yes" for the top two and a number for the bottom three. Are you using a Tuning Adapter?

    Also, if a CableCARD isn't authorized for a channel, you can have all good numbers in DVR Diagnostics but still no video because the decryption to get that channel isn't authorized.
     
  7. dolphin

    dolphin New Member

    74
    0
    Dec 3, 2007
    Signal Lock and Program Lock for both tuners is YES. For the PIDs:
    PCR PID 0x1242
    Audio PID 0x1243
    Video PID 0x1242
     

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