New Bolts MAY Have Better Fans

Discussion in 'TiVo Bolt DVR/Streamer' started by V7Goose, May 11, 2017.

  1. SalemCat

    SalemCat Active Member

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    Apr 13, 2006

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    Pots are stupid.

    They are essentially coils of wire. The only way they slow anything down is by converting current into heat.

    They are essentially Resistors that can be adjusted.

    They can't make a fan run faster, only slower - and yes, quieter.

    So if you start with a fan that is more than adequate for cooling, but is noisy, and then slow it down with a pot, so everything is quieter, but still cool enough - the pot has done its job.

    But that's the only thing it can do.
     
  2. SalemCat

    SalemCat Active Member

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    Apr 13, 2006
    Anyhow, my ears suck from years of Rock-N-Roll, so I'm not the best judge of Fan Noise being annoying. I just crank them up and watch the degrees drop. :p
     
  3. Redoctobyr

    Redoctobyr Active Member

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    Jun 21, 2008
    Sorry, I didn't explain fully. I know that pots are just dumb adjustable resistors, and can't speed the fan up. But:

    - The stock fan is a "normal" fan (2 wires), but the Bolt controls the speed using Pulse Width Modulation (PWM) of the 12V power that it receives. They turn the 12V on/off very quickly to speed the fan up, or slow it down. If the Bolt chooses, it can run it at full-speed, using a full & constant 12V, but most of the time the fan is running slower (as an example, getting the 12V only 50% of the time, and getting 0V the other 50%). You'll hear this full speed noise as the Bolt initially boots up.

    - What I was describing was based on using a second, always-on, constant 12V source, like the plug on the motherboard that powers the hard drive. Split that 12V source, and power the fan from that. That should run the fan at full-speed, for max cooling. But as I learned, even with the quieter XS-2 fan, it would still be audible. So I was contemplating using that 12V source, but lowering the voltage a little bit with a pot, to get more cooling than typical, but less noise than if using the full 12V.
     
  4. SalemCat

    SalemCat Active Member

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    Apr 13, 2006
    Thank you for clarifying your plan.

    It makes sense now.

    If I encounter excessive heat I'll try that - though I'm not that sensitive to fan noise, and would not use a pot.

    If you do identify a suitable pot, though, I'm certain there are many members who would appreciate a recommendation.
     
  5. ropedrag

    ropedrag New Member

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    Oct 6, 2003
    Seattle

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    Bought a Bolt 3 weeks ago and was struck on how noisy the thing is, google search etc.... must be the fan like everyone is saying. Ordered up a couple of Fractal Silent Series R3's (extra one for a friend). So I swap the fan and guess what, still noisy as hell, try the 2nd fan I bought and again the same annoying noise. So finding some time I removed the cover for further investigation and discovered the noise is actually coming off the board. I've enough lead wire to hold the fan some distance from the unit to determine it isn't the fan making the noise its the whiny pitched noise that could fool us into thinking its a fan motor going right off the board. Further searching and I've read that several people have changed the fan without a noticeable improvement but while I'm mechanically inclined I have no knowledge of what could be making the noise, all I know is that it's annoying as hell.

    Just so its clear, fan plugged into the 2 pin connection generates a whiny pitched noise from the board, does not matter if the fan is OEM or other,... fan not plugged in equals no noise.

    My Bolt lives in an AV cabinet out of sight so I've removed the fan and left the cover off. I'll monitor the temp
     
    Last edited: Jun 11, 2017
  6. Redoctobyr

    Redoctobyr Active Member

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    Jun 21, 2008
    Yes, this electronic buzzing noise has been discussed in at least one recent fan-noise thread. Powering the fan with an external source, or the Bolt's USB port, for instance, will eliminate the noise.

    The 2-pin fan plug is controlled using PWM to turn the 12V source on and off very quickly, to allow varying the fan speed. It is apparently this switching that produces the electronic buzzing sound. Some Bolts are either different, however, or some of us are less sensitive, as I did not notice this buzzing noise with mine, just the fan noise.

    In post #63, and some earlier posts in this thread, I was describing a possible approach for getting a full 12V source inside the Bolt's case, by tapping into the power supply for the hard drive. I got a splitter cable for $4 on Newegg that I think would let me tap into that 12V source, without making any permanent changes to the Bolt or its cables. But I haven't tried the cable yet, as I'm not sure if I want my fan running at the full 12V speed. And opening the Bolt's case makes me a bit nervous about damaging the clips, so I'm not just taking it apart for fun.
     
  7. ropedrag

    ropedrag New Member

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    Oct 6, 2003
    Seattle
    Thanks Redoctobyr, good information. I like the idea of powering the fan off the usb, seems like a reasonable fix but I'll have to figure it out which is the hard part.

    And yes its quite easy to snap off the plastic tabs on the smaller of the two covers, cover removal is super easy just needs a little TLC on that one part.
     
  8. Redoctobyr

    Redoctobyr Active Member

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    Jun 21, 2008
    Can't look it up right now, but in one of the recent fan threads, I thought one person posted some info about how they used the USB port to power their fan. That might provide a starting point.

    The main thing I like about using the Bolt's USB port is that it has power whenever the Bolt is on. If using an external power supply instead (also a viable option, with more choices for voltage and therefore fan speed), that supply could fail, shutting down the fan, without you realizing it. Probably a low risk, but still not ideal. If you just wanted 12V, you *could* tap into the output of the Bolt's actual power supply. That supply is guaranteed to be on when the Bolt is running, of course.
     

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