Bad tuner or CableCARD?

Discussion in 'TiVo Series3 HDTV DVRs' started by Dan203, Jan 14, 2012.

  1. Dan203

    Dan203 Super Moderator Staff Member TCF Club

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    So last night I noticed that a few of the programs I've recorded over the last couple of days are truncated and listed as "(partial)". After some investigation I discover that every channel I tune using one of the two tuners is all pixelated and choppy, while everything tuned with the other is fine. I figure a reboot might be in order so I pull the plug and wait it out. Now every few seconds I get an error about how CableCARD #2 is having an issue (161-4). I tried rebooting again with the CableCARDs removed and then reinserting as suggested in another thread, same problem. The only way I could get the error to go away was to, quickly, go to live TV and change that tuner to an analog station. I know this says it's a CableCARD issue in the error, but I'm wondering if it might be a bad tuner. Because for the brief moments I can get it to work everything associated with that tuner is still all pixelated. Also for the last couple of months I've been getting errors and glitches in my recordings even though the signal strength on all stations is listed at 95 or higher.

    If this is the tuner then do they even offer output of warranty repair on S3 units anymore? (original OLED s3) This unit has lifetime so it would suck to have to trash it completely.

    Dan
     
  2. L David Matheny

    L David Matheny Active Member

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    I know little about CableCARDs because I don't have cable. But what would happen if you swapped your two CableCARDs around? Would that mess up the pairings? If you have any broadcast stations reasonably close, could you remove the CableCARDs and try connecting an antenna for test purposes? Or for that matter could you just connect your cable without the CableCARDs for test purposes? You wouldn't have any usable guide, but that wouldn't matter. Or would just powering up the TiVo without the CableCARDs mess up the pairings? I'm assuming that you have already swapped the cables feeding the CableCARDs to rule out anything like a bad cable.
     
  3. unitron

    unitron Well-Known Member

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    Some of the people with DirecTiVos a few years ago had a one tuner worked, the other one didn't, problem, and, like many other strange symptoms, the problem turned out to be the power supply (even though the power supply doesn't have separate sections for each tuner), specifically one or more bad capacitors in the power supply.

    Look for a thread titled "broken" in the help forum for a great picture of how subtle the visual difference is between a bad cap and one that hasn't gone bad yet.

    That said (and you really should take off the lid and eyball them just to be sure), in your case I'd suspect, from what I've seen in the posts of others forced to use cable cards, that you've got one that's faulty or not paired quite completely right.
     
  4. Dan203

    Dan203 Super Moderator Staff Member TCF Club

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    I forgot to mention that I've been using this TiVo with these same two CableCARDs (they're S-cards) for about 5 years now. So the CableCARD isn't "faulty". If it's bad then it just recently went bad.

    Also I've done a bit more testing and found that this tuner works just fine on analog stations, but it messes up if I tune any digital stations, even the local channels which are not encrypted and don't actually need the CableCARD. Also I'm starting to see a bit of pixelation on the other tuner as well. It's not nearly as bad, but it's causing minor dropouts in my recordings which cause them to lose audio

    Unfortunately I think swapping the cards would screw up their pairing and make it so I could no longer tune any of the premium channels, even after I swap them back. So I'm reluctant to try that test.

    The capacitor issue is an interesting idea. If all it is is the power supply I can get a new one of those from Weaknees for $100. However I'd like to know for sure that's a potential problem. I sent Weaknees a PM asking if they've heard of this same issue occuring on S3 units. If they have I'll bite the bullet and buy one.

    Although before I do that I'll probably bite the bullet and try swapping the CableCARDs. Even if they kill my ability to tune premiums I have to know for sure whether or not it's the CableCARD before I do anything. Does anyone know if I'm right about the CableCARD pairing getting screwed up after a swap even if I swap them right back?

    Dan
     
  5. unitron

    unitron Well-Known Member

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    Well, you can bring up my posts and search for "capacitor" and find plenty of mention where I've replied to others who've discovered capacitor disease in their 240s, 540s, 648s, and 652s, there's even a whole thread from a year or two ago about the problem cropping up in S3 platform units.

    And you can fix it for about $10 worth of parts and some solder.

    (That's why I'm currently able to use a formerly dead HD I got for the cost of shipping and a lifetimed 240 and 540 I got cheap.)

    If the power supply is the problem.

    As for it being a cable card thing, I'm just going by what I've read here of the experiences of people who actually have them and what solved their problem.
     
  6. Dan203

    Dan203 Super Moderator Staff Member TCF Club

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    OK I decided to say f*ck it and I swapped the two cards. The error remained on tuner 0 even with the cards switched, so I'm pretty sure this is a tuner error not a CableCARD error. :(

    I guess the next step is to crack it open and inspect the power supply for bulging capacitors.

    Dan
     
  7. unitron

    unitron Well-Known Member

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    One of the DirecTiVo models was famous for a bad power supply cap being the cause of one tuner failing and the other working fine even though both fed off of the same rail on the power supply.
     
  8. Speed Daemon

    Speed Daemon New Member

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    IIRC the CableCard never touches the signal stream. It's only job is to decode a 56-bit DES hash. OTOH it has to get its data from a tuner, so...

    With all this talk about bad caps, shouldn't there be a more definitive way to test a TiVo PSU? I have a DMM and a 'scope, how could I use them to troubleshoot? Couldn't one of the new PC power supply testers be used with the right adapter cables?
     
  9. unitron

    unitron Well-Known Member

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    If you have a meter and scope and know how to use them, the orange is +3.3V, the red is +5V and the yellow is +12, and they should have little to no ripple.

    Start with hard drive disconnected (and therefore not drawing current).

    If the rails look good on the scope and are within, say plus or minus .25V, power down, hook up the drive, and check again.
     
  10. Speed Daemon

    Speed Daemon New Member

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    Thanks! One advantage of using a scope vs. a digital display or idiot light is that I can see stuff like ripple and hash.

    But aren't these switching power supplies? Don't they need a load in order to get an accurate reading? Or will the mobo draw enough without the HD connected?
     
  11. unitron

    unitron Well-Known Member

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    The hard drive is just a load in parallel on the +5V and +12V rails along with parts of the motherboard.

    A TiVo will start up just fine without the drive hooked up, it just won't go beyond the "Welcome, Powering Up" screen.

    I say start with the drive disconnected to establish a baseline, so if you see a change when the load of the drive is added, you know the power supply can't handle it, which indicates that it's going bad.

    If you walk in a room and flip the light switch and lights in other rooms in the house dim for a just a moment until its filament heats up and its resisitance increases, you know the house's electrical supply doesn't have enough "oomph" for what you're drawing from it.
     

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