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Increasingly Pixelated - PSU caps FIXED

Discussion in 'TiVo Series3 HDTV DVRs' started by guava, Mar 26, 2014.

  1. guava

    guava New Member

    18
    0
    Dec 31, 2007
    Thanks for all the posts on the bad PSU caps. I didn't think my problem was a PSU but gladly it was.(I know analog repair)

    The problem:

    Over 3 days my output went from stuttering to pixelated garbage, like someone kept on hitting pause very fast. Optimum changed my cable cards and claimed the signal was strong enough, and blamed the TIVO.

    2 company tug and war:

    Tivo had me check out the SNR and Signal Strength. Strength jumped around from 0-33 to 95. SNR I think was varying from 35-8(memory not great).
    They said it was the cable company, and I tried to inquire if it could be the box.... NOoooooooooo we are confident in our TIVO Boxes. (well you should have used some nice Panasonic El caps then)

    The Fix and Results:

    So I replaced only 6 caps. Looking from the front down.... the 2 2200uF caps on the right; replaced with 25V caps (one calls for 16V). front left, 2 470uF/16V caps with the same. And the 2 2200 6.3V caps under the heat sink with 16V ones.

    WoooooWhooooooo, now kicking back with some food and French Soccer.

    OK signal strength locked in at 100 and SNR at 35-36
    RS both at zero
    (before it they were like 20-60K I think)

    Maybe it's just satisfaction of a job well done, but it looks better. I do plan to replace all those el-caps. I should never have underestimated a PSU cap upgrade. Always the first thing I do for my audio gear that comes through my door.
     
  2. unitron

    unitron Active Member

    16,389
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    Apr 28, 2006
    semi-coastal NC
    If you've had occasion to work on any consumer electronics gear over the past decade and a half, I'd think you'd have been more receptive from the beginning to the possibility that "capacitor plague" was cause of the trouble.
     
  3. guava

    guava New Member

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    Dec 31, 2007
    Do you mean flat panels and massed produced stuff?

    My EE skills are limited, and hence feel like such a hack going for the El-caps first.... But it's usually the problem. Probably even more so with these always on devices.
     
  4. unitron

    unitron Active Member

    16,389
    2
    Apr 28, 2006
    semi-coastal NC
    Check out the wikipedia page on "capacitor plague" to learn about the zillions of bad caps that flooded the supply chain during the last decade and a half.

    Or check the main page at badcaps.net
     
  5. fred2

    fred2 New Member

    509
    0
    Jan 20, 2006
    Hopefully, I can jump into this thread. My Series 3 has suddenly decided that pixelation adds to my enjoyment of programming. In some cases that might be true but that aside, I guess I need to investigate the inside of my tivo and its capacitors. Since replaying the bad sections shows the same patterns, etc, I don't suspect the hard drive (which I did replace about a year ago???).

    I notice that the OP mentioned replacing capacitors of certain values with new ones with different (increased?) values. Is that a standard procedure that adds to reliability? How does one figure out what's what in that regard. I've never done any kind of electronics work like this so besides de-soldering and re-soldering, the values of capacitors is something I don't know anything about.

    Also, where are folks going for these new parts?

    Thanks in advance.
     
  6. dlfl

    dlfl Cranky old novice

    7,004
    19
    Jul 6, 2006
    Near...
    You don't say which Series 3 (there are 3 models). For the model 652xxxxx, Tivo HD, see this:
    http://www.tivocommunity.com/tivo-vb/showthread.php?p=9964473#post9964473
    As you see there are at least 2 different PSU models and Digi-Key is a source. Mouser is also a source I believe. You MUST get "Low ESR" high temp (105C rating) caps.

    There are parts lists for the other Series 3 models. Don't know if they're in that same thread or elsewhere.
     
  7. fred2

    fred2 New Member

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    0
    Jan 20, 2006
    Thanks for the quick reply. Okay, guess I need to narrow down my model. Front of tivo: 3HD.

    Tivo info: 648-0001-8026-0DB8

    Anywhere else it might display info needed for this determination?
     
  8. dlfl

    dlfl Cranky old novice

    7,004
    19
    Jul 6, 2006
    Near...
    That info number isn't a model number but the 648 strongly suggests you have a model 648xxxx, Tivo S3 or "OLED" model. I think the model number is on the back of the unit (?).

    There will be a different parts list for the S3 PSU, perhaps search in the thread already linked or someone will post the link for you.

    Meanwhile you can look for bulging caps. Here's a photo of what to look for:
    http://www.tivocommunity.com/tivo-vb/showthread.php?p=8750894#post8750894
     
  9. fred2

    fred2 New Member

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    Jan 20, 2006
    Thanks. I guess I will take the tivo out of my "system" so that I can find out what's inside and what condition it is in.

    Maybe I should just give up on Tivo and torrent what I need!!!
     
  10. guava

    guava New Member

    18
    0
    Dec 31, 2007
    As a general rule for cap replacement:

    keep value the same and got to higher voltage as space allows.
    and 105 Degree caps will be better.

    For me, replacing the caps in the lower right corner of the PSU fixed my problem.(looking at unit from the front and above). to the right of the heat sink.

    There was a thread on the exact values and part numbers to replace.
     
  11. fred2

    fred2 New Member

    509
    0
    Jan 20, 2006
    Thanks. I just have to take some time with the unit. And then, obviously ordering parts and hitting radio shack for a desolder kit and maybe a better soldering iron!
     
  12. HerronScott

    HerronScott Well-Known Member

    2,789
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    Jan 1, 2002
    Staunton, VA
  13. unitron

    unitron Active Member

    16,389
    2
    Apr 28, 2006
    semi-coastal NC
    That number is the TiVo Service Number which is unique to your machine, but since it starts with 648 we know that your machine is a TCD648250 (probably with a B or b on the end).

    It's the original Series 3, also called the S3 OLED, because of the Organic Light Emitting Diode display (the clock) on the front.

    There seems to be only one model of power supply ever used with those, the one for which HerronScott linked to a list of caps.

    And that thing at Radio Shack with the squeeze bulb can be used both to remove the old solder and to heat up the new work enough to melt new solder onto it. Use solder with nothing but lead and tin (and a rosin core).
     
  14. fred2

    fred2 New Member

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    0
    Jan 20, 2006
    Thanks for the parts listing, Scott, and the confirmation, unitron - yes, I have the LED display clock on the front.
     

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