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Tivo Series 3 - Bad capacitors in power supply

Discussion in 'TiVo Help Center' started by johnsom, Jul 25, 2011.

  1. unitron

    unitron Active Member

    16,387
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    Apr 28, 2006
    semi-coastal NC
    Picked up from where? Radio Shack?

    You need to use low ESR caps rated for 105 degrees Celsius/centigrade.

    Most, and likely all of what you'd find at Radio Shack won't be low ESR and will only be rated for 85 degrees.

    The uF needs to be the same.


    To replace a 10V cap, you could go with 16V, maybe 25, 35's kind of pushing it.

    When not operated near the rated voltage the oxide layer that works as an insulator between the conductive surfaces doesn't get and remain fully and properly formed, or something like that (been a long time since 'tronics class)

    And of course you have to observe proper polarity when you replace.

    You may have another cap that went, or is going, bad, that isn't showing visual signs, so checking the +5V and +12V outputs with a voltmeter is recommended.
     
  2. dlfl

    dlfl Cranky old novice

    6,997
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    Jul 6, 2006
    Near...
    I'm surprised the 35V caps weren't MUCH larger than the 10V versions, to the point of being hard to fit in. When charged to rated voltage the 35V cap contains 10 times as much energy (goes with voltage squared). You don't store 10X the energy in about the same volume unless you're compromising somewhere else in the cap design (e.g., not low-ESR and lower temp rating).
     
  3. bhw

    bhw New Member

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    Dec 15, 2006
    Replaced all the caps and the 12v (yellow wire) is only measuring around 7v and not steady 5v (red), 3v (orange), and 7v (grey) are all steady. Still getting a ticking sound out of the supply. Any ideas as to why the 12v is not coming up would be appreciated.
     
  4. unitron

    unitron Active Member

    16,387
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    Apr 28, 2006
    semi-coastal NC
    That 7 on the grey might be a little lower than it's supposed to be by a Volt or two, see if there's a sticker on the really big cap on the input side or some silk-screening on the board that lists voltages and amperages. The lowest amp figure will be the grey wire if it's not second lowest to the 3.3. The yellow and the red are the big guns.

    If the grey is low, it's almost an absolute certainty that it's a side effect of whatever's drawing down the +12.

    Possibly some component other than a capacitor has gone bad. Perhaps a capacitor going bad caused that other component to go bad.

    But more likely...

    Perhaps you put one of the capacitors in "backwards", polarity wise. There's a reason why one of the leads has either minus or plus signs down the side of body nearest it.

    Perhaps you put a couple of the caps where each other should have gone, like a 1000uf where a 2200 should be and vice versa.

    Perhaps you got some solder where it shouldn't be, or didn't get some where it should be.

    That ticking might be part of the supply turning on, detecting too heavy a current flow, shutting down, turning back on, lather, rinse, repeat.

    (Or to be really technical, magnetostriction caused by the L, R, and R process)

    Do those measurements both with and without the drive hooked up.

    Report back.
     
  5. bhw

    bhw New Member

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    Dec 15, 2006
    Thanks unitron for the quick reply. solder and cap polarity was first thing I double checked. I didn't notice the label on the big cap. It reads 3.3v-4.1a, 5.0v-8.4a, 7.5-1.9a, 12v-1.0a (orange/red/grey/yellow). I'm measuring the supply unloaded. Diodes all look good. Next to look at the MOSFET voltage regulators. Hard to debug w/o schematic.
     
  6. unitron

    unitron Active Member

    16,387
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    Apr 28, 2006
    semi-coastal NC
    I feel ya, brother.

    Good news is, you only need to worry about the 12V section.
     
  7. Trogdor1083

    Trogdor1083 New Member

    13
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    Mar 24, 2013
    Yes, Radio Shack...They fit alright but are about twice the size of the original guys. Will order low ESR ones at 10v now. Anyone have recommendations on where to get a good set online or possibly a retail store to pick up in the Stamford CT/Fairfield County region? Need two 1000uf 10v low esr.

    Since Unitron thinks its possible it may need more than just the two caps, here's some background:

    The system starting acting up over a year ago and it came to an abrupt failure back in December. 3 year lifetime was about to expire but I got it working again by Plug and Pray (maybe I should have traded in for same model?).

    Two days ago the system was loading everything really slowly. Also, the 30 second skip button reset itself to scan to the end of the program (weird?) and I couldn't get it to go back to that functionality. I unplugged and plugged it back in, but that was my fatal mistake so I read up on the caps and looked inside my unit and found that C403 and C503 were bulging and one was leaking.

    Before I replaced the two caps, the fan and hard drive turned on, but no joy on the system starting up and no power to USB ports (I had external fans connected for rack ventilation).

    After I replaced the caps with the Radio Shack ones (i.e. wrong voltage and not low esr), the hard drive still turned on but the fan did not turn on anymore.

    Also, I don't own a voltmeter :eek:
     
  8. unitron

    unitron Active Member

    16,387
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    Apr 28, 2006
    semi-coastal NC
    Somebody around here somewhere made a list of the caps for the 652 (not to be confused with the other list somebody made which is for the 648), but the 652, the S3 HD, used two different power supplies from two different sub-contractors.

    Look at the circuit board and post the brand and model number of the power supply and we'll go from there.
     
  9. Trogdor1083

    Trogdor1083 New Member

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    Mar 24, 2013
    3Y Power Technology, P/N: 3850158312GP, REV: 1. It also says CP-1319R2 (not sure if that's the model number or not).
     
  10. unitron

    unitron Active Member

    16,387
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    Apr 28, 2006
    semi-coastal NC
    Okay, that's the one made by the same outfit that made the 648 supply.

    I've got one sitting out on the bench at the moment, so I'll check some old posts to see if anyone's already compiled a list for that model and if not I'll sit down with the bright light and magnifier and figure out which ones are on the +5V and +12V outputs and post that ('cause those are the ones likeliest to be bad if any are), but it might take a day or three.
     
  11. HerronScott

    HerronScott Well-Known Member

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    Jan 1, 2002
    Staunton, VA
    That would be great since then we'd have all 3 of the S3 power supplies documented.

    Scott
     
  12. unitron

    unitron Active Member

    16,387
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    Apr 28, 2006
    semi-coastal NC
    Do you happen to remember, and can you provide the link, to where the 652 cap list that's already been posted is?

    If not, don't worry about it, I'll find it myself.
     
  13. HerronScott

    HerronScott Well-Known Member

    2,783
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    Jan 1, 2002
    Staunton, VA
    I posted a list for the Acbel S3 HD power supply 2 pages back in this thread.

    http://www.tivocommunity.com/tivo-vb/showthread.php?p=9518796#post9518796

    That was just based on the visual inspection of the S3 HD that I bought my son. I've not actually replaced the capacitors in that one so was hoping someone would add some confirmation at some point.

    Scott
     
  14. unitron

    unitron Active Member

    16,387
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    Apr 28, 2006
    semi-coastal NC
    Thanks.
     
  15. Spiff

    Spiff Pawn in game of life

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    Fox Cities,...
    I just replaced these exact three caps tonight. A power outage two weeks ago left my S3 unable to boot. Worked like a charm. I am so glad I read this site. This was my one lifetimed unit I have in service and I'm happy to have it back.
     
  16. Trogdor1083

    Trogdor1083 New Member

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    Mar 24, 2013
    While I'm thinking of it, I wanted to mention that when I removed the power supply I also took a look at other parts of the motherboard that might be causing power problems. I went to replace the CR2032 battery on the mother board and snapped the positive arm off the battery holder. Can this be soldered back together or do I have to replace the entire battery holder (by removing the motherboard!)? Since it works the same as a battery on every motherboard (holds the static memory during power loss) is it even essential for the Tivo to run?
     
  17. Apr 1, 2013 #157 of 532
    ljiminez

    ljiminez New Member

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    Jun 23, 2007
    My 6 year old Tivo S3 has recently started having scrolling horizontal lines in the picture. It does not matter if the show is playing or if the show is on pause. Could bad caps cause this problem ?

    Here is a short video showing the problem. It takes around 5 to 10 seconds before the video starts playing.

    http://www.screencast.com/t/Oj8tluSGm

    If you think caps could possible be the problem I will attempt the replacement surgery. But anything more involved than cap replacement is probably beyond my skill level. Thanks for your help.

    Nez
     
  18. Apr 1, 2013 #158 of 532
    steve614

    steve614 what ru lookin at?

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    Dallas, TX
    With the S3 and TivoHD, it is a high probability that it could be bad capacitors - Do the lines appear in Live TV and recorded shows?
     
  19. Apr 1, 2013 #159 of 532
    evanborkow

    evanborkow Member

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    Have you tried a different source other than the Tivo like plugging the cable directly into the TV?
     
  20. Apr 1, 2013 #160 of 532
    HerronScott

    HerronScott Well-Known Member

    2,783
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    Jan 1, 2002
    Staunton, VA
    That looks similar to what we saw for a while before the power supply finally died altogether on our S3 OLED. Ours were pretty faint so didn't really think too much about it until it died. Once I replaced the caps, lines were gone as well.

    Scott
     

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