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Tivo HD Pixelation Troubleshooting

Discussion in 'TiVo Series3 HDTV DVRs' started by Chimpware, Aug 3, 2007.

  1. astroglide

    astroglide New Member

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    Jun 20, 2005
    I'm sorry to report that you've lost me.

    I took a couple of pictures, front and back, and circled the three offenders. The primary (C701) is visibly leaking from the pic. The other two (C401 and C402) are lightly bulging. They're obscured here, but they're the only two beneath the heat sink. Based on this information and these pics, could I trouble you to tell me which others you'd replace? Thx!

    [​IMG]
    [​IMG]
     
  2. unitron

    unitron Active Member

    16,389
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    Apr 28, 2006
    semi-coastal NC
    Without either a schematic of it to study, or having it in my hands, I don't know what circuits any of the others are in, so I don't know which ones are likely culprits, if any.

    So the best advice I can give under the circumstances of you not being able to figure out what's paralled across the +5 and +12 Volt outputs is to just replace those 3.

    Get replacements with the same uF rating, the same or slightly higher voltage rating, rated for 105 degrees Centigrade, and specifically described as being low ESR (Equivalent Series Resistance), and check the height and diameter to make sure they'll fit where the old ones were.

    And be sure to observe polarity when putting in the new ones.

    Which means putting the - lead where the - lead on the old one was and the + lead where the + lead on the old one was.

    Getting it backwards could cause them to explode.
     
  3. astroglide

    astroglide New Member

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    Jun 20, 2005
    Nod. TYVM again for the pointers.
     
  4. GerryFR

    GerryFR New Member

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    Aug 7, 2003
    I was not given direct access to the channel spectrum meter that the Cox tech was using for testing my cable channels, but from what I could see, the meter was displaying multiple channel levels at the same time. The tech, also, only needed one look to tell that the channel signal levels were unbalanced. This tech specialized in Tivo units and was the first Cox tech that I found that knew this much about these units.

    Before the tech worked on my cable input, I checked the turner information for data on two different channels. One of these channels was working fine, and the other was dropping out. It turned out that both channels were being transmitted on the same switched channel (222). The power level of these two channels were listed as being almost the same, but I do not know if the power level listed was for this particular switched channel or the overall input power level of the combined combined signal levels.

    I doubt that the cable amplifiers, being used by cox, amplify each channel individually, and since the higher frequency cable channels would get attenuated the most, going through cable, it would seem likely that these channels would get sent out at higher power levels than the lower frequency channels. Another factor in my problems may be because on my street, all the utilities are underground. The cable box, for our neighborhood, is in my front yard, and so it would figure that I would probably have the highest higher frequency channel power levels in the neighborhood. I know that this box has the main amplifier for this area, because two Cox techs spend most of the afternoon, last year, replacing this amp. Because of these coaxial signal level long distance losses, A Tivo owner, further down the street, may not have had this problem at all. It also turned out that the Tivo (S3), that had the longest Cox cable run (an extra 75 feet) had the least amount of channel problems. Since the cable channels get sent to my Tivos by the Cox Cisco tuners, it would seem possible that these devices may also be part of this problem.

    I have subsequently found out that my HD Tivo continues to have numerous channel videos breaks up and this hangs up the recording on this unit. This Tivo has all of its' channels back, but they all do not work well. Tonight, I attached a coax cable to the input cable, for this Tivo, and ran this 50 foot cable to my S3 Tivo. The S3 Tivo continued to work properly so I may have other problems with the HD Tivo. At least I have one of my Tivos working!

    This kind of picture problem is not confined to Tivos, locally. I have friends around 10 miles away from here and they also complain about their Cox channels breaking up and dropping out.
     
  5. dlfl

    dlfl Cranky old novice

    6,997
    18
    Jul 6, 2006
    Near...
    What do you mean by "channel 222"? Do you mean 222 MHz frequency? The RF frequency applies to a 6 MHz wide QAM channel which may contain 2 to 6 TV channels and may be either SDV or not. I would assume the signal strength reported by TiVo has to apply to the overall 6 MHz QAM channel because the signal never exists as an analog (i.e., RF) signal beyond the QAM channel point -- it is detected as a digital signal and processed digitally from there on to separate the TV channels.

    But: what was the signal strength number for "channel 222" ??
    What you're discussing is the "tilt" situation as detailed by lrhorer in the post I linked earlier in this thread. And it applies whether the distribution cables are underground or above ground.
    :confused: What are you referring to as a "Cox Cisco tuner"?
    I would agree with your deduction except for the effect of the 50 foot cable, which like all cables, will change the tilt, i.e., the ratio of high- to low frequency strengths. To rule this out run the end of the added 50 ft cable into the "bad" tivo and see what happens. Again, what actual signal strengths (and SNR and RS Error Counts) are reported for the various channels on the "good" and "bad" TiVo's?
    This suggests a general Cox problem, although people 10 miles away are not on the same node as you so different cable plant equipment is involved for them. What about the people within 500 ft of you?
     
  6. Oct 6, 2012 #1566 of 1597
    astroglide

    astroglide New Member

    31
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    Jun 20, 2005
    Forgot to reply follow up: I replaced those three caps, and all is well again. Thanks!!
     
  7. Oct 6, 2012 #1567 of 1597
    GerryFR

    GerryFR New Member

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    Aug 7, 2003
    I fixed the last of my Tivo HD picture breakup problems today. Earlier in the week, I put an attenuator on the input cable line and this got my Tivo out of its' slow motion response to my remote control. The signal level had been sitting at 100, but after the attenuation, the signal level was at 92. Today, I removed the external hard drive from this Tivo and the picture problems all went away. I had run the Tivo hard drive diagnostic program, on this external drive, several times, and it always passed. I guess that I no longer understand what constitutes a bad hard drive on Tivo systems. Since my HD Tivo only has 20 hours of HD video recording, without the external hard drive, I am going to replace this small internal hard drive with a much larger hard drive as I no longer trust external hard drives.

    Since the Western Digital external hard drives are supposed to be built to work like the Tivo hard drives, I wonder why both of the Western Digital external drives, that I have owned, both died in a little over 2 years (out of warranty) while all of my Tivo hard drives (in 4 different Tivo units) lasted between 4 and 5 years.

    Jerry
     
  8. Oct 6, 2012 #1568 of 1597
    unitron

    unitron Active Member

    16,389
    2
    Apr 28, 2006
    semi-coastal NC
    The problem with the TiVo-specific WD external drives may not be the actual drive inside the enclosure itself.

    It might be the eSATA cable or either of the jacks into which it plugs or maybe it's just the particular span each recording across both drives scheme they use.

    Or maybe the enclosure power supply is nothing to write home about.
     
  9. Feb 8, 2013 #1569 of 1597
    Jerry Wilson

    Jerry Wilson New Member

    25
    0
    Jan 7, 2005
    I started having this problem a few months ago which gradually got worse. I had the local cable guy out and he replaced the two cards, apparently high quality with gold (quality disputed) plated connections. My picture quality has greatly improved. The pixelation problem seems to of greatly diminished, only time will tell. I will add the the worst pixelation was concentrated on MSNBC.:up:

    I would like to add this box goes back quit a few years, note my "Join Date" on the left.
     
  10. dlfl

    dlfl Cranky old novice

    6,997
    18
    Jul 6, 2006
    Near...
    You should eliminate power supply problems due to "capacitor disease". Open the box and look at the capacitors in the PS. Even slight bulging as shown in the following post (#2) means the cap should be replaced:
    http://www.tivocommunity.com/tivo-vb/showthread.php?p=8750894#post8750894
     
  11. Feb 9, 2014 #1571 of 1597
    slyone

    slyone New Member

    241
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    Jul 22, 2005
    Just found this thread, My TivoHD has wicked pixelation last few weeks:( Had timewarner check all levels on line-OK-I had to disconnect tivo its soo bad! WTF! Whats the fix?? Should I get a new one and can I transfer my lifetime??? This is BS & sucks:(
     
  12. Feb 9, 2014 #1572 of 1597
    SCSIRAID

    SCSIRAID Active Member

    2,321
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    Feb 2, 2003
    Vero Beach, FL
    Have you watched live and then checked DVR Diags for RS Uncorrected counts? Also monitored Signal to Noise Ratio?

    Have u taken a look at the power supply caps for swelling and leakage?

    These would be the first things I would do.
     
  13. Feb 9, 2014 #1573 of 1597
    slyone

    slyone New Member

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    Jul 22, 2005
    Hi, no I dont know anything about that? I upgraded the hdd when first bought 5-6 yrs ago & ran a laptop cooler under it. I found when I unplugged cooler at usb it got instantly better but still apparent:(
     
  14. Feb 9, 2014 #1574 of 1597
    L David Matheny

    L David Matheny Active Member

    1,589
    2
    Jan 29, 2011
    SE Ohio
    It's hard to imagine that reduced cooling could cure the pixelation, but I suppose the USB laptop cooler could have been generating noise or (more likely) the extra load was causing problems for a marginal power supply in the TiVo. As SCSIRAID said, read up on power supply problems and inspect the power supply capacitors.
     
  15. unitron

    unitron Active Member

    16,389
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    Apr 28, 2006
    semi-coastal NC
    Run the cooler again, but this time power it off of something besides the TiVo's USB jack, and see if it doesn't run the same amount of better.

    If so, you almost certainly need to fix the power supply before seeing if there's anything else wrong.
     
  16. slyone

    slyone New Member

    241
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    Jul 22, 2005
    hey guys finally able to get back to this (missing lots of shows).:( Got the ole 565 model fired up;) hehe. I do have 5 caps slightly bulging upwards, C-501, 502, 504 and C-503 & 403. Ya think this could be my culprit for severe pixelation? I'm thinking I buy the 5 and prolly have a local tv shop guy r&r them. Found this from wobly
    Tivo HD Digi-Key PN Manufacturer PN
    C501 10V 2200uf RLS 0720 P15323CT-ND EEU-FR1A222LB
    C502 10V 2200uf RLS 0720 P15323CT-ND EEU-FR1A222LB
    C504 10V 2200uf RLS 0720 P15323CT-ND EEU-FR1A222LB
    C403 10V 1000uf RLS 0736 P14378-ND EEU-FR1A102L
    C503 10V 1000uf RLS 0736 P14378-ND EEU-FR1A102L
     

    Attached Files:

  17. unitron

    unitron Active Member

    16,389
    2
    Apr 28, 2006
    semi-coastal NC
    By 565 you mean 652, right?

    There are 2 different HD and HD XL power supplies, made by two different companies, and the cap list for one is not the cap list for the other, however, both lists are on this website somewhere or maybe more than one somewhere.

    Consult page 8 of this thread

    http://www.tivocommunity.com/tivo-vb/showthread.php?t=473394

    and the ones you want to order are...

    Skip the biggest one which is rated for 200 Volts--it ony deals with 60Hz to 120Hz frequency, so it's not working very hard, and should still be just fine and very likely to stay that way.

    Get replacements for all of the rest of the caps on the board except the really little ones, so, in other words, all those medium size ones near both sides of the heat sink(s).

    That way you don't have to worry about replacing 4 or 5 now only to have one or two others go bad in a couple of months from now.

    And skim through the rest of that thread until you understand why you need Low ESR caps rated for 105 degrees Celsius.
     
  18. slyone

    slyone New Member

    241
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    Jul 22, 2005
    By 565 I meant I'm temp using my old RS-TX20 for now. and Yes, My tivo HD 652-160 has the bad P/S capacitors. It has a 3Y p/s.
    update; I ordered the 9 caps from digi & will get 'er done:) Thanks for the excellent guidance everyone! This board ROCKS!!
     

    Attached Files:

  19. slyone

    slyone New Member

    241
    0
    Jul 22, 2005
    I received my 9 capacitors today from Digi-key which was very nicely packaged too! I went to a reputable electronics repair shop and had them install in an hr and $50.00. Powered up & found no remote control action? rechecked everything but no luck, tv picture looks good but no way to input to Tivo? I even checked batteries in remote.....any ideas? Thanks
     
  20. unitron

    unitron Active Member

    16,389
    2
    Apr 28, 2006
    semi-coastal NC
    Check the ribbon cable from the motherboard to the front panel, make sure it hasn't been dislodged at either end.

    Do this with the TiVo unplugged.
     

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