Tivo reboots when coax connected

Discussion in 'TiVo Premiere DVRs' started by ae6dx, Jul 29, 2016.

  1. ae6dx

    ae6dx New Member

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    Jul 20, 2005

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    I have a Tivo premiere XL with cable signal being delivered via clear QAM that is actually an OTA signal but sent out via QAM. I live on a university campus and they don't want to subscribe to cable and do not provide cable cards.

    My Tivo initially worked fine minus guide data. But lately it just kept rebooting. I finally figured out it worked fine without the coax attached. I've tried adding signal attenuates but am having no luck. As I understand it this is the only Tivo that will support QAM without a cable card.

    Sometimes I can eventually get it to work but it takes many reboots. Is there anything else I can do? Is there maybe another brand of DVR?

    I have tried my own antenna but my appartment is in a bad spot to put up my own.
     
  2. JoeKustra

    JoeKustra in the other Alabama TCF Club

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    Ashland, PA...
    There is line of Magnavox/Funai DVD HDD Recorders that have QAM tuners but no cable card slot. This is one example:
    http://www.ebay.com/itm/Magnavox-MD...309105?hash=item33bc0d20f1:g:YxEAAOSwtnpXlfqU
    They are PSIP only, no guide. Sort of a VCR like box. To see all the models:
    http://www.avsforum.com/forum/106-d...-513-2160a-2160-2080-philips-3576-3575-a.html
     
  3. L David Matheny

    L David Matheny Active Member

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    Rebooting only when the coax is attached could indicate a grounding problem. Does the coax come through a grounding block that is properly grounded to the same system ground as the receptacle that powers the TiVo (and other equipment)? DC offset or significant noise on the grounds can cause strange problems.
     
  4. ae6dx

    ae6dx New Member

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    I'm not sure. It's just the cable outlet in my apartment. When it works I can go a few months without any problems. Then all of a sudden it happens again. The university used to have a regular cable subscription. The problems started after they switched to clear QAM.
     
  5. unitron

    unitron Well-Known Member

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    If this were a Series 2 or Series 3 I'd immediately suspect the power supply capacitors going bad.

    Does anyone around there know anything about electronics troubleshooting and repair?


    You need to have someone set a voltmeter for AC, at least 150 Volts, and, with the co-ax disconnected from the TiVo, check between TiVo RF input ground and co-ax outer shell and between input ground and co-ax center conductor, and between input center conductor and both ground and center on the co-ax, and between co-ax ground and center conductor and between RF input ground and center conductor.


    And then they need to set it on DC 15 Volts or higher and backprobe the plug from the power supply to the motherboard.

    Negative Ground is the black wires, yellow is supposed to be + 12 V, red, + 5 V, orange, if present, + 3.3 V.
     
  6. ae6dx

    ae6dx New Member

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    Jul 20, 2005
    I don't know enough about electronics to take the box apart. Can this be tested without doing that? From the previous reply I thought it was indicating a problem with the line coming in. But are you saying it's the Tivo box itself that's bad?
     
  7. unitron

    unitron Well-Known Member

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    The part I said to do with the voltmeter set on AC for 120 V or higher can be done without opening up the TiVo.

    Unbend a small paper clip and stick it into the center of the RF input to bring a connection to it out where you can probe it.

    The RF connector is that threaded nipple thingie.
     
  8. HomeUser

    HomeUser Active Member

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    Disconnect the Coax Cable then with the DVR plugged in Measure between the threaded part of the cable and connector on the DVR, check for both AC and DC. I suspect you will find 12V DC from the buildings AMP. If you don't have a meter look for any spark when the coax touches the metal part of the DVR's connector.

    If you do find voltage there and the school is unable to fix it this might help Ground Loop Isolator for Cable TV applications
     
  9. Aug 2, 2016 #9 of 17
    Teeps

    Teeps Well-Known Member

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    Have you used one of those isolators?
     
  10. lpwcomp

    lpwcomp Well-Known Member

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    John's...
    Could be the disk drive. When the cable is not connected, it is not recording at all. The times when it is working, it may not be encountering the bad sectors or it could be marginal and sometimes work.
     
  11. HomeUser

    HomeUser Active Member

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    No, I got the Cable Company to fix the issue that was causing the Modem to reboot, it also cleared up several problems with the DVR's.

    The Cable Co's fix was replacing the device on the pole that was leaking the power to the cable plus driving in a new grounding rod.
     
  12. tivoyahoo

    tivoyahoo New Member

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    what happens when you try the antenna? just try to get a single channel, because that would help isolate the issue and whether the hard drive was an issue as lpwcomp suggested...

    the hard drive fail might have just coincided with the clear qam switch. couldn't this also be a qam tuner fail? or maybe the line got some sort of unintended jolt in the switchover process and fried your tuner.

    is anybody else on campus using a dvr? Series3 and TivoHD should pick up clear qam. models 648, 652, 658. you may be able to pick up one of those cheap. as in $5 cheap from a thrift store or online, cheaper than an electronics repair shop running a diagnostic. Or pick up another premiere unsubscribed. if you connect you can see if it replicates the fail of your premiere. the idea is just to test to try to isolate whether it's the signal or your tivo that's the problem and that's a cheap way to find out. even an inactive tivo will receive and buffer clear qam. but getting a 648, 652, 658 subscribed is a different proposition than a premiere so getting another used premiere should be on your radar. but first confirm if the ota tuner and hard drive are working properly on your existing premiere with any kind of signal you can pull even if it means for just 5 minutes hanging something out the window - higher the better. or taking it to another location to connect.
     
  13. tivoyahoo

    tivoyahoo New Member

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    does your tv have a clear qam tuner? if you're picking up the channels on the tv, then the issue is likely with your tivo, not the signal. And I believe a roamio will pick up clear qam - you just have to manually add them to your channel list after they are detected in a scan.
     
  14. lpwcomp

    lpwcomp Well-Known Member

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    John's...
    A QAM tuner fail is not going to cause reboots.
     
  15. tivoyahoo

    tivoyahoo New Member

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    I agree. was sounding like improper voltage or maybe a jolt came down the line at some point through the tuner causing damage that now somehow might short out somewhere along the way causing a reboot.

    and maybe better not to connect the cable signal to a tv to test since if there is improper voltage, it could likewise damage the tv.

    but rereading the OP follow up...
    it sounds like the tuner and dvr works for awhile with clear qam and then goes into reboots. so yes, that sounds like hard drive so that's why I was suggesting an antenna connection which has a separate rf infput and like you said if that causes a fail due to writing to the drive then the clear qam signal isn't to blame. Or just pull the drive and run diagnostics on the drive if getting a single channel to come in over antenna is too much hassle. but sounds like opening the box and pulling the drive would be the tougher task.

    Or shouldn't playback of recordings with the coax disconnected be enough to trigger a drive fail? if he had a big folder full of recordings and played the entire folder continuously. or do you think it would take writing to empty sectors that are bad to trigger reboot? if he can trigger reboots without the cable connected, then again points to the drive. but if it is the drive, sounds like he isn't comfortable pulling it.
     
  16. tivoyahoo

    tivoyahoo New Member

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    2 tuner premiere was the last model to support both analog cable & digital cable - see comparison chart:
    http://www.weaknees.com/tivo-premiere-comparison.php

    This thread is about the successor model, roamio not supporting analog cable:
    http://www.tivocommunity.com/tivo-vb/showthread.php?t=508345

    not clear if the channels you are trying to receive are digital qam (unencrypted/clear - no cable card needed) or analog.

    Here's a thread on a roamio rebooting where it turned out to be power supply:
    http://www.tivocommunity.com/tivo-vb/showthread.php?t=542153

    although can't a bad power supply also lead to hard drive problems?

    if you aren't comfortable opening up the premiere and trying to diagnose, then I guess the question becomes: what is tivo's policy on replacing premieres or offering an upgrade? although in this case if the channels are analog then an upgrade isn't what you want. does the premiere have lifetime subscription? or monthly/annual?
     
  17. lpwcomp

    lpwcomp Well-Known Member

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    John's...
    Playback of a recording that is on sectors that have since gone bad can cause a reboot but that doesn't seem to be what is happening here.
     

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