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What can cause reboots besides psu/hard drive?

Discussion in 'TiVo Series3 HDTV DVRs' started by CrashHD, Jun 29, 2014.

  1. CrashHD

    CrashHD I am the me.

    757
    0
    Nov 10, 2006
    MO, USA
    I have a 652 unit suffering frequent reboots. The PSU has been recapped, to no improvement. That PSU was then swapped with an identical unit that has had no symptoms in 6 months runtime. Issue still occurs.

    I just today put a fresh image on another hard drive, and it just rebooted on me again.

    I've never seen one that couldn't be fixed with a hard drive, or PSU caps. Any ideas, or is this one just sadly fit for the recycle bin?
     
  2. dlfl

    dlfl Cranky old novice

    6,997
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    Jul 6, 2006
    Near...
    Have you measured the PSU voltages? Actually scoping them would be better as there could be transient components that don't show up in a DC voltmeter measurement.

    Some have claimed that cable signal glitches can cause reboots. What signal strengths are you seeing?
     
  3. CrashHD

    CrashHD I am the me.

    757
    0
    Nov 10, 2006
    MO, USA
    I haven't the means to scope them. I could measure them, though. I'll have to bring my meter home from work first.
    I have two TivoHD's (652's) and one is unaffected. Both PSU units have been totally recapped. Both PSU's work just fine, without any issue, in Tivo "A", but Tivo "B" is frequently rebooting.

    I am using them on Antenna. I haven't checked signal strengths, but I know there are two stations that are a little on the weak side (will cut out with blocky picture in storms). Both Tivos are hooked to the same antenna. I suppose I could change their physical positions, and see if that makes a difference.
     
  4. CrashHD

    CrashHD I am the me.

    757
    0
    Nov 10, 2006
    MO, USA
    In case it's relevant, sometimes it's not a reboot. Sometimes it freezes, and must be power cycled.
     
  5. dlfl

    dlfl Cranky old novice

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    Jul 6, 2006
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    If signal strength is causing reboots it would be from excess signal, which is not usually the case with antenna signals -- but not impossible I guess. So it would be good to check your signal strengths.

    I think the PSU voltages are a more likely suspect. You should see 5V, 3.3V and 12.0V. Tolerances are +/-5% on the first two. I'm not sure whether the tolerance on the 12V is 5% or 10%. You should measure them with all loads still connected (beware of shock hazard). There is a connector on the motherboard that brings all the voltages in from the PSU and you can get access by inserting (thin) voltmeter probes into the back of that connector. Black is ground, Red is 5V, Yellow is 12V and orange is 3.3V.
     
  6. squint

    squint New Member

    846
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    Jun 15, 2008
    I would try a different image. I've had to try more than one image in the past. It's a long shot but it doesn't take very much time.

    Any chance it's overheating?

    With most of the usual causes eliminated, it might be a solder joint starting to fail somewhere on the motherboard. At that point, it might be time to donate it to science. I'm assuming from the trouble you've gone to that this is a lifetime unit?
     
  7. replaytv

    replaytv gun talk ignore list

    4,402
    0
    Feb 20, 2011
    Denver ish...
    I would carefully inspect the mother board looking for burnt components. And if you didn't find any look for a cold solder joint. Sometimes I have seen the top blown off of integrated circuits due to overheating.

    [media]http://softsolder.files.wordpress.com/2010/12/cimg5578-cold-solder-joint-in-usb-memory.jpg[/media]
     
  8. nooneuknow

    nooneuknow TiVo User Since 2007

    3,554
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    Feb 5, 2011
    Cox Cable...
    If you are not equipped to scope the outputs of a power supply for ripple, switch your multimeter to the AC voltage setting, and test the output voltage outputs again, after checking on the DC setting.

    In a perfect world, with perfectly designed power supplies, you would get no reading with the meter on AC. In the real world, with "lowest possible cost" designed power supplies, it's "the less, the better".

    I always forget the thresholds, as they vary. But, if you happen to have two identical power supplies, one working well, and the other not, you could do a comparison between the two.

    It's not a true ripple and noise test. But, it's better than nothing. I suggest using Google and a calculator, if you don't have a known-good one to compare readings with.

    If the power supply makes audible noise in operation, take a non-conductive object, like a plastic ball-point-pen, and gently press around on the components, and the board itself, listening for the noise to go away, get worse, or otherwise change. This could lead you to a cold solder joint, and a fix, by resoldering it. It could also lead to a perfectly good component, like a ferrite choke, that just needs some hot glue to secure the ferrite, and get rid of the audible noise (which won't fix anything, except for the audible noise).
     
  9. replaytv

    replaytv gun talk ignore list

    4,402
    0
    Feb 20, 2011
    Denver ish...
    Using your PC as a oscilloscope-

    I see on Windows Media player under the 'Visualization' option there is, 'Bars and Waves', and 'Scope'. Is is possible to connect to the audio input of your Windows computer to the voltage that you want to look at and see if is correct?
     
  10. unitron

    unitron Active Member

    16,387
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    Apr 28, 2006
    semi-coastal NC
    Only if you build some interface/isolation circuitry to go between the two.
     
  11. nooneuknow

    nooneuknow TiVo User Since 2007

    3,554
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    Feb 5, 2011
    Cox Cable...
    Yeah, even my Fluke combo meter/scope uses opto-isolation on the serial link for just sending the data (not the actual voltage/current) to a computer (for long-term readings and creating graphs).
     
  12. CrashHD

    CrashHD I am the me.

    757
    0
    Nov 10, 2006
    MO, USA
    I am running off a 30 year old antenna that was here when I moved in, and I had to install an adjustable output distribution amp to get any meaningful signal at all. I did have to dial it up to near maximum to get all channels to come in, and this distribution amp is in addition to whatever ancient preamp is on top of the antenna tower. It stands to reason a setup like this could be introducing a fair amount of noise. Replacing the antenna has been on my todo list, but as always, there's too much above it on the list. I will bring my meter home from work tomorrow to check voltages (dc and ripple).

    Meanwhile, I'm tuning this unit to specific channels and setting 12 hour recordings, to look for a pattern, and see if I can correlate reboots to which channels are tuned.
     
  13. dlfl

    dlfl Cranky old novice

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    What are the signal strength readings in DVR diagnostics? If less than 100 your signals are not too hot. Even readings of 100 don't mean too hot but indicate that is a possibility.

    If you're within 15 miles of transmitter towers try just using a cheap indoor antenna, to eliminate any noise introduced by your amplifiers.

    However if two Tivo's using the same antenna input signals are acting differently it's probably not a signal quality issue.
     
  14. unitron

    unitron Active Member

    16,387
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    Apr 28, 2006
    semi-coastal NC
    The antenna may not need replacing nearly as much as the pre-amp and co-ax hanging off of it.

    Have you ever checked the power supply for that pre-amp?
     
  15. timhbtr53

    timhbtr53 Grumpy Old Man

    307
    1
    Apr 24, 2014
    In the Deep...
    Just for ha ha sake have you tried moving the drive from TiVo a to TiVo b to see if you still have the problem?
     

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