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Channels randomly not tuning, signal lock=no

Discussion in 'TiVo Help Center' started by brianm729, Jul 10, 2013.

  1. brianm729

    brianm729 New Member

    36
    0
    Jul 10, 2013
    I have tried the search but couldn't find anything. I have been having this problem for about the last month but have not been able to resolve it. I have a Series 3 with two Comcast cable cards. It has been working fine for almost 2 years but in the last month channels will randomly not tune. I can be watching something a the screen will go black, or I will try to change the channel and not be able to tune. I have had Comcast out twice and they replaced the cards and ran new cable to be sure the signal strength is strong. When I look at signal strength it shows me 0 and "No digital signal". The DVR diagnostics screen is showing signal lock=no. Usually I can restart the TiVo or wait and the channel will come back. It seems to happen to all channels randomly, but only a few channels at a time. I don't know what to do next. Can anyone please help me? Thanks in advance.
     
  2. crak

    crak New Member

    18
    0
    Feb 12, 2006
    Did you ever fix your problem? I have the same thing happening to me this last week. I've been going back and forth with Comcast pairing and activating the cards but it always goes back to not tuning.
     
  3. unitron

    unitron Active Member

    16,389
    2
    Apr 28, 2006
    semi-coastal NC
    In DVR diagnostics, is one tuner showing an inability to decide on modulation mode, or center frequency?
     
  4. crak

    crak New Member

    18
    0
    Feb 12, 2006
    If I tune one turner to a working channel and the other tuner to a not working channel I get in the working tuner Modulation: 8-VSB, on the tuner with the black screen channel I get nothing in almost every thing, the only things that have some info are
    CableCARD Association: None
    SNR: 36DB
    RS Uncorrected: 0
    RC Corrected: 0
    RC State: Available
    Current Tuning Status: Not Tuned: Wrong Card State
    Tune State: Not Tuned:
    CCI Byte: N/A
    Pending Tune Status: No tune pending
     
  5. unitron

    unitron Active Member

    16,389
    2
    Apr 28, 2006
    semi-coastal NC
    Make sure it's the channels that are not working, and not one of the tuners. In other words, make sure you can move the symptoms from one tuner to the other. Try putting one tuner on one non-working channel and toggle the Live TV button and put the other tuner on a different non-working channel and check both in DVR diagnostics for the same bad results.
     
  6. buscuitboy

    buscuitboy New Member

    736
    0
    Aug 8, 2005
    Atlanta area
    I am having a similar problem with a Series 3 TiVo HD (lifetimed). When I receive the channels, my signal strength is great. However, channels will randomly tune in and/or not tune in. Sometimes, even when a HD channel is not working, but then I tune in the SD digital version of the same channel, the HD version will then start working again.

    For example, channel 803 (ABC) might stop tuning in. However, if I go to the SD digital version of it on ch3 and then try to go back to 803, both will be working.

    I am wondering if this problem could be related to the power supply issues prevalent in Series 3 Tivos. ANY chance this could be the problem? I actually have a identical spare working TiVO HD that is not subscribed too and sitting in a closet. I could swap power supplies if needed.
     
  7. unitron

    unitron Active Member

    16,389
    2
    Apr 28, 2006
    semi-coastal NC
    If they're both 652s, swap supplies long enough to see if that fixes the problem, at least, 'cause that's easy to do.

    Power supply problems cause strange symptoms (unless the problem is that the power supply is completely dead), so maybe it's the cause.

    Or maybe TiVo sent it the "Time to buy an S5, S3 suicide signal".

    I think I'm kidding about that last part, but I'm beginning to wonder.
     
  8. buscuitboy

    buscuitboy New Member

    736
    0
    Aug 8, 2005
    Atlanta area
    Yea, while I figured you were kidding, you never know these days. This S3 that is giving me random channel issues is in a guest bedroom so not used a lot. I would like to just keep it that way, but maybe I am being "encouraged" to upgrade :)
     
  9. unitron

    unitron Active Member

    16,389
    2
    Apr 28, 2006
    semi-coastal NC
    Actually I suspect what might be going on is failure of some of the Surface Mount Device capacitors on the motherboard itself, and that's at least an entire order of magnitude more difficult to troubleshoot and deal with than power supply caps.

    But the timing sure is "co-incidental".
     
  10. buscuitboy

    buscuitboy New Member

    736
    0
    Aug 8, 2005
    Atlanta area
    OK, I swapped out my lifetime Series 3 HD with an identical unsubscribed Series 3 HD. Called Comcast and paired a cable card (S-card) in it. All seemed to work fine & I was able to get the channels (but with no program guide or recording capability since its unsubscribed), but then the same problem started happening....random channel lock problems.

    Therefore, it has to be one of two problems....either there is a problem with my coax cable line or a problem with the motherboard as just described.

    I personally don't think its the coax line as its a brand new line that was installed directly by Comcast about a year ago. I even swapped it out with another coaxial line that was made by a Comcast tech. There are no splitters on it and it goes directly from the TiVo to the Comcast box on the side of the house. They even had to drill a whole from the outside of the house since there was really no outlet in that room.

    Oh well. My next move is to try my Series 3 OLED TiVo in that same room and see how it performs. If it works fine (like its doing now in another room), then I would have to agree that it could be an issue with the motherboard.
     
  11. buscuitboy

    buscuitboy New Member

    736
    0
    Aug 8, 2005
    Atlanta area
    OK, I am wondering if this channel locking issue (now on two of my Series 3 TiVO HDs) is related to the recent 11.0k firmware update for these units.

    Would reimaging a drive with an older firmware version be doable & maybe essentially "downgrade" the unit. Or will the firmware get updated automatically again and no real choice on the matter. I am thinking the later.

    I was thinking of upgrading my TiVo HD's hard drive from 160GB to a 500GB one so was hoping I could maybe kill two birds with one stone, but maybe it doesn't work this way in the long run.
     
  12. joanzen

    joanzen New Member

    18
    0
    May 1, 2002
    Boynton...
    Hey. Check out this thread for others who are having issues with Comcast in PBC. I am also in PBC and have been having the same tuning issues with my S3, HD, and Premiere. Some have reported that Comcast has sent new cable card firmware, which seems to have fixed the problem. Unfortunately, I am traveling at the moment and can't check to see if I have received the new firmware.

    http://www.tivocommunity.com/tivo-vb/showthread.php?t=510784
     

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