High Pitch Sound - not fan or Hard Drive

Discussion in 'TiVo Series3 HDTV DVRs' started by Eire1780, Jan 8, 2019.

  1. Jan 8, 2019 #1 of 11
    Eire1780

    Eire1780 New Member

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    Hello,
    I had an issue this week with my Tivo Series 3 HD (TCD648250B) (with lifetime subscription) where it would no longer boot. I just fixed that with a hard drive upgrade.

    But now I am getting a high pitch sound from the device. It's pitch/volume does seem to vary with the length of time that the Tivo is plugged in.

    I disconnected the new drive and the cooling fan but the high pitched sound is still there when I plug in the Tivo (to test).

    I was hoping that someone might know what might be causing this and how I can fix it.
    Thanks
     
  2. Jan 8, 2019 #2 of 11
    Eire1780

    Eire1780 New Member

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    Not sure if this helps, but when I (internally) disconnected the main board from the power supply board and plug in the Tivo, there is no high pitched sound (just a quiet clicking sound). Everything reconnected the high pitch sound is back.
     
  3. Jan 8, 2019 #3 of 11
    unitron

    unitron Well-Known Member

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    You probably need to read up on capacitor replacement for Series 3 TiVo power supplies.

    If you can figure out which end of the soldering iron gets too hot to hold it by, you can probably do the job yourself.
     
  4. Jan 8, 2019 #4 of 11
    Eire1780

    Eire1780 New Member

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    Thank you unitron, will do. They definitely don't look flat... 2019 01 08 - Tivo S3 Capacitors bulge.jpg
     
  5. Jan 8, 2019 #5 of 11
    Eire1780

    Eire1780 New Member

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    Just in case it is also relevant, I get my signal from OTA and since October 2018 or so, what were solid signals for the channels I receive, they started to break up (around the time the new OTA Tivo box was released)... just to be the devil's advocate I'll ask it...
    a) is there any connection or just similar timing?
    b) could the high pitch sound come from a failing OTA tuner (not sure if that's the correct term)?
    Thanks
     
  6. Jan 8, 2019 #6 of 11
    unitron

    unitron Well-Known Member

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    Strongly suspect the noise is coming from the power supply--it might be what's called magnetostriction, which is what made old picture tube TVs have a high pitched noise that younger people could sometimes hear. You have a coil of wire wrapped around an metal core, and the current through the coil, which is a high frequency alternating current, creates a rapidly expanding and contracting magnetic field which causes the metal of the core to try to move to follow it, so it's basically vibrating at that high frequency, which pushes and pulls on the air around it, and when something pushes and pulls on air, you get sound.

    Even if it's not magnetostriction, it's probably still something caused by those faulty capacitors.

    You need to solve your power supply problem before you try to diagnose any remaining problems, if they still remain after fixing the power supply.
     
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  7. Jan 8, 2019 #7 of 11
    Eire1780

    Eire1780 New Member

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    Jul 29, 2009
    Thanks for the update. I just ordered the replacement capacitors.
     
  8. Jan 9, 2019 #8 of 11
    unitron

    unitron Well-Known Member

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    Since there are two different power supplies used on the 652/658 models, I hope you made sure to find the right list for whichever one it is that your unit has.
     
  9. Jan 9, 2019 #9 of 11
    Teeps

    Teeps Well-Known Member

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    Yeah, those with the peaked domes are bad for sure.
     
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  10. Eire1780

    Eire1780 New Member

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    Jul 29, 2009
    Hmm, I did realize that I had the TCD648250B model and ordered the capacitors from that thread. But I didn't realize that there were more than one revision of that model's power supply. The capacitors I ordered were for "SPWR-00008-000 Rev A3" and I have "SPWR-00008-000 Rev A2" - not sure if they use the same ones yet...
     
  11. unitron

    unitron Well-Known Member

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    My bad, I somehow missed that you'd specified having a 648 and was thinking you had a 652 for some reason.

    You should be good.

    The 648 supply and the 652/658 supplies are very similar, same size, same shape, same screw hole locations, same plug, but there's only one 648 model (though more than one revision of that model is possible, but cap list should be the same).

    The 648 PS has a wire the others don't and should only be used on a 648, lest that extra wire short to something, perhaps.

    It's the 652/658 that can use either of two different models, made by two different suppliers, interchangeably, but each has its own cap list and you have to get the right one, but I'm just putting that here for the benefit of other readers.
     

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