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How is System Temperature Measured?

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by MurrayW, Jul 14, 2010.

  1. MurrayW

    MurrayW Legend

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    Apr 13, 2006
    I recently got an HR24 and was happy to see that the internal temperature reading was ~110F compared to my H20's and HR21 (all with eSata's attached using MX1 enclosures) that typically read between 125 and 130F. A few weeks after I got the HR24, I hooked up an eSata (using a different enclosure than the MX1) and an AM21 and noticed the temperature is now reading between 130 and 135F.

    In the original configuration, an HR20 was resting on top of the HR24 with 4 spacers in each corner about 1/2" in height so that the HR20 was not sitting directly on the HR24. The new configuration is: HR24-->AM21-->Spacers-->HR20.

    If the temperature is the eSata hard drive temperature, I will see what I can do to address that, otherwise, I will look at my stacking.

    thanks,
    Murray
     
  2. hdtvfan0001

    hdtvfan0001 Well-Known Member

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    Temps are measured via a sensor inside the HD DVR's and reported in the Info/Test screen on the Setup menu.

    Previous generation HD DVRs have registered temps anywhere from 108 - 130 degrees, with temps less than 130 degrees being preferred.

    A fair amount of what drives the temp variations is the hard drives used (the most recent in the HR24's are "green"), as well as the power supply and actual DVR model case design / fan location.

    For example, the HR24-100 and HR24-500 have their cooling fan in 2 different places....yet...the internal temps are both generally within 5 degrees or so of each other with both models.

    When you "stack" hardware, and depending on the fan location, you can either help or compound the temp heat results, depending on the specific models and layout in the "stack. Placing several devices in an enclosed cabinet area can also compound the heat situation. In general...stacking adds the potential heat of the lower units to the upper units, since heat rises.
     
  3. MurrayW

    MurrayW Legend

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    Thanks, since the eSata hard-drive isn't the cause of the increased heat of the HR24, I will work on seeing if I can improve the air flow around the HR24. The temperature of the upper component, HR20, was not affected by the new configuration.

    For those of you that have an AM21, do you normally have the AM21 on the bottom or top of your HRx?
     
  4. Stuart Sweet

    Stuart Sweet The Shadow Knows!

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    I think most folks put the AM21 on top but those who have put it underneath haven't had too much trouble.
     
  5. P Smith

    P Smith Mr. FixAnything

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    I did ask owners of DVR with eSATA disks - quickly connect the eSATA disk to PC and obtain SMART data what including the temp - it will prove/disprove that suggestion if the temp coming from a drive; there is 50/50 chances of on-board temp sensor.
    But no one did that and we continue speculating.
     
  6. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    "Well" someone with an eSATA removed the cable to the drive and the temp reading either showed zero or some very low number [32 or 34] and when connected again returned to the normal reading.
     
  7. hdtvfan0001

    hdtvfan0001 Well-Known Member

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    How cool is that!!! :D

    <pun intended>
     
  8. MurrayW

    MurrayW Legend

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    You mean removed without shutting down first then rebooting off of the internal drive?

    Tonight I will try powering off the HR24, disconnecting the eSata then booting back up with the internal drive to compare temperatures and report my findings.
     
  9. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    This shouldn't show any change since the reading is off the internal drive and this is what was disconnected in the earlier post. It's not going to give you a temp reading through the eSATA cable.
     
  10. P Smith

    P Smith Mr. FixAnything

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    If you would post a snapshots from that reading, I could tell you if it was Celsius degree. "showed zero" - means your program is not reliable and you should use other one.
     
  11. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    I didn't do this, but read the post from who had, or maybe it was a PM from them.
     
  12. MurrayW

    MurrayW Legend

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    This was in response to P Smith's 50:50 comment which I read it to mean that he wasn't sure that the temperature reading was from an on-board temperature sensor and may possibly be the hard drive temperature. Maybe I misinterpreted what he meant.
     
  13. Richierich

    Richierich Hall Of Fame

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    One of my HR24-500s shows a reading of 126 Degrees sitting on a Cool Pad but running with a 2TB Hard Drive. I may just put it under the HR23-700 with the Cool Pad in between them and see if the temp changes.

    If you disconnect the Internal Hard Drive the temperature reading will Default to a Reading of 77 Degrees.
     
  14. P Smith

    P Smith Mr. FixAnything

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    If we can get SMARTs from both drives same minute after shutdown, we could deduct if there is third source - on-board chip.
     
  15. MurrayW

    MurrayW Legend

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    I could possibly get you a SMART reading from my eSata 1 minute after shutdown but can't do it for my internal drive. So hooking my eSata up to my laptop won't corrupt what is already on the eSata drive somehow? If you outline the exact steps that you want me to take, I can give it a try. Do I need to download an external program to get the SMART temperature data or can Windows 7 do that natively?
     
  16. P Smith

    P Smith Mr. FixAnything

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    Not sure about W7 capability, I'm using SW Victoria under Windows XP.

    The steps would be: prepare long SATA to what-your-notebook support for internal HDD SMART reading and SATA power [5/12V] cable with PS;
    - open a cover right after turn off power (hope the DVR is owned)
    - connect SATA/power cables to PC/PS and internal HDD, then read SMART data - take snapshot;
    - serve eSATA drive for obtain other SMART log - take another snapshot
    - post both pictures here :)
     
  17. MurrayW

    MurrayW Legend

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    I don't own my HR24 and don't plan to open it up, that is why I said I couldn't do this for my internal drive.
     
  18. Stuart Sweet

    Stuart Sweet The Shadow Knows!

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    Sounds like the right way to go :)
     
  19. MurrayW

    MurrayW Legend

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    OK, it took me a while to do my testing. This is what I have:
    HR24-500
    AM21 on top of the HR24-500
    HR20-700 on top of the AM21 with ~1/2" spacers in each corner to elevate it off of the AM21.
    2TB Hitachi drive in a Thermaltake eSata enclosure about 1 foot above both DVR's:
    http://www.thermaltakeusa.com/ProductBanner/storage/ST0005U.jpg

    When I go to the HR24's menu and look at the internal temperature it consistently reads 136 when the eSata drive is attached. Here's what I did (all temperature readings are what is displayed on the HR24's menu):

    1. Turned off the HR24-500, disconnected the eSata and rebooted off of the internal drive. Temperature = 106 and stayed at 106 for about 10 minutes.
    2. Turned off the HR24-500, reconnected the eSata and rebooted. I wish I would have waited a while for the external drive to cool to room temperature, but I didn't. It was still pretty warm to the touch after having been off for about 15 minutes. The temperature reading when the HR24 first booted up was 126.
    3. I waited about 15 minutes looking at the temperature readings every few minutes and the temperature rose gradually from 126 up to 135.
    4. I put a small table fan blowing directly on the external eSata drive, waited for about 15 minutes (checking temperature ever few minutes) and the temperature dropped from 135 to 106. It stayed at 106 for the next 1 hour that I had the fan blowing on it. The external drive was cool to the touch (probably less than 106 on the outside part of it that I touched).
    5. Turned the fan off and the temperature gradually drifted back to 136 (didn't take any pictures of this).

    From this experiment, it appears to me that the temperature reading on the menu screen DOES take into effect the external drive's temperature. Maybe there are 2 readings and it reports the highest of the two, which would explain why the reading got back to 106 with the fan blowing on the drive even though by touch I would estimate the drive was close to room temperature.

    It would be interesting if someone else with an eSata would repeat this experiment to see if they get similar results.
     

    Attached Files:

  20. TomCat

    TomCat Broadcast Engineer

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    Thanks, Murray, that's a great report, but I think you might have buried the lead. It really doesn't matter too much how or where the temp reading is generated; the bottom line is that a small fan (I prefer the $9 clip-on fans from Walmart) solves any heat-related problem so that you can stop worrying about potential premature heat-related failure and go back to watching DirecTV :).
     

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