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Temperature Issues

Discussion in 'Other HD Receiver Support Forum (811, 921, 942)' started by skassan, Nov 25, 2004.

  1. skassan

    skassan AllStar

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    Jan 10, 2004
    I just had to replace my unit after working fine for 5 months. It suddenly refused to recognize the smart card. When pulling the old unit out, I noticed that it was very hot. It lives in an entertainment center. The clearance on the sides is about an inch. I've removed some other components to give it more room on the top. I've also added a timer to shut the power off during non-user hours (11 pm to 6 am.) I'm also thinking of adding a fan or two behing the unit to help circulate fresh air to the sides, where the venting holes are?

    Any comments? Will the daily power cycle help or hurt? Are the fans necessary? Will they help? Is this box not meant to sit in a home entertainment center?
     
  2. ClaudeR

    ClaudeR Godfather

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    Dec 6, 2003
    I will be getting a new one next week, and I am very afraid of the noise level. I am planning on getting a super long DVI cable so I can put the box in a different room. I have also read about others who put the unit on coasters (or something) to get more airflow underneath. This box is HUGE. There's lots of vent holes, so I think it gets airflow, especially with the loud fan running in it. Is your entertainment center enclosed? They also say not to put anything on top of it.

    As far as the refurb goes, that USUALLY means that there was a real person that actually looked at it and hand tested it. Many times that is a good thing for electronics.
     
  3. JD Robinson

    JD Robinson Mentor

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    Nov 13, 2004
    Mine sits in an entertainment center, and has given me no problem. I don't find the noise to be a problem at all. It could be my imagination, but it seems as if the units internal fans spin up in response to ambient heat (when my amplifier is on, e.g.).

    IMO, supplemental fans would be a good idea if you can stand the noise. Mouser Electronics has a wide variety of cfm and noise index fans.

    On the other side of the coin, so long as Dish is willing to replace it, whadda you care? :)
     
  4. Jim_R

    Jim_R Mentor

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    Feb 13, 2004
    Wouldn't it be relatively simple to put a thermometer near the 921, to get an idea of ambient temps? The 921 does have a fan, after all it is basically a PC. As to noise level, I am not bothered by it. My 921 sits on top of a large rear projection television that is roughly 10 feet away from the couch. In general, I'd say it is quieter than most desktop PCs. When you are watching TV, you won't even know it's there. But I imagine if someone were to install it in a quiet area (like a bedroom) it could become annoying.
     
  5. ClaudeR

    ClaudeR Godfather

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    Dec 6, 2003
    Skannan - Don't forget that the software upgrades and guid info are downloaded during the night. Putting the timer on may not be the best idea - most people seem to wait anxiously for the software updates.
     
  6. ClaudeR

    ClaudeR Godfather

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    Dec 6, 2003
    But there is only a one year warranty. Seems to me that if you get a "good box" out the door, you may want to take good care of it, so you don't get a lemon refurb in the 11th month...

    As we all now, heat is one of the worst life degrading things you can do to electronics.

    Unless of course, you pay for the warranty, then never mind what I said.
     
  7. bytre

    bytre Legend

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    Sep 10, 2003
    I've got mine in an a/v cabinet, I cut out most of the back panel so most of it is exposed behind the 921. It gets warm, but not hot.
     
  8. JD Robinson

    JD Robinson Mentor

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    Nov 13, 2004
    Yeah, my quip was definitely tongue-in-cheek, for one thing since it's such a pain to "break in" a replacement. Also because I've personally found Dish's support to be very willing to help and replace equipement and I wouldn't seriously encourage abusing the system.

    I know it's unscientific, but an EE friend of mine once told me that if an IC is too hot to touch, then it's already been damaged. I would interpret that to mean that if the case is at all "hot" to the touch, it's probably already past it's safe temp.

    I just hung a thermometer inside my cabinet and it's a modest 85 deg F. I'll see what it says when I hear the fan "rev up" tonight. (Or when I imagine I hear it... :))
     
  9. Jacob S

    Jacob S Hall Of Fame

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    Apr 14, 2002
    When I did the card swap on my 721 I noticed on the front of the card directly from the other side where the chip is at that there is a black square almost burnt looking. When I used to do receiver reboots by pulling the card and pushing it back in I would notice that some of the cards look a little yellow around the chip as if it was getting a bit hot or something but havent experienced a failure with them.
     
  10. David_Levin

    David_Levin Icon/Supporter DBSTalk Gold Club

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    Apr 22, 2002
    Scott Kassan,

    You need to tell us more about your entertainment center. Is it enclosed (closed in back and glass doors in front)?

    How about other components? Is there an amplifier in the rack roasting it?

    Basically, the 921 should have cool air around it? Your asking for trouble if all it can do is circulate it's own heat.

    I have my racks set up with fans pushing external air in and across the components. Order is Fan, 921, then Amp, so the Amp heat doesn't get to the 921.
     
  11. deweybrunner

    deweybrunner Legend

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    Feb 8, 2004
    I have my 921 in an enclosed intertainment center along with an amplifier. I have glass doors on front with cracks all way around. I purchased 5" magnetic fan from radio shack, cut a hole in back, and direct flow out. I also put control where I could regulate the speed of the fan, turning it up enough to keep the unit cool. This fan is so quiet you can hardly notice it. The 921 cannot be allowed to overheat, even though it has internal fans. They just circulate the hot air. Mine was very easy to install. I took off the solid back and put in the fan. It works great.
     
  12. skassan

    skassan AllStar

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    Jan 10, 2004
    Will I still get the download after the unit is turned on, or is that a one-shot deal?

    Each component is enclosed on five sides; the front is open. Each component is on its own shelf, and the amplifier is on the shelf above the 921, so it's not getting any additional heat from other components. As I said, there's about 1" clearance on the sides. There's about 5" of free space in the back and now that I've rearranged things, and about 8" on top. All shelves, sides, and back are wood.
     
  13. David_Levin

    David_Levin Icon/Supporter DBSTalk Gold Club

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    Apr 22, 2002
    I had a 508 that was overheating when enclosed on 5 sides (front open). I think even with the front open the heat tended to "pool" around the unit. I ended up opening up the back so there could be cross ventilation.

    (you're amp really needs to breathe too - those puppies really generate some heat)
     
  14. skassan

    skassan AllStar

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    Jan 10, 2004
    Well, I just remembered that I have an IR thermometer for shooting tire temps for one of my other money-sucking hobbies. I took some readings yesterday after the unit was powered for 12 hours. The highest temp I saw was 105F. I never took a temp reading in the old configuration, but by touch, this configuation is noticably cooler that when I removed the defective unit. Am I correct in assuming that as long as I'm below 120 I should be ok, and no fans are needed in the current configuration?
     
  15. boylehome

    boylehome Hall Of Fame/Supporter

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    Jul 16, 2004
    I questioned E* tech. support months back. They said that it isn't uncommon for the unit to run up to 120 degrees but that it should shut down around 120+. During the hot summer months, I had to leave the door to my entertainment center open. I'm considering sawing holes, one high, one low and installing two fans for air exchange.
     
  16. FaxMan

    FaxMan Legend

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    Oct 13, 2003
  17. SimpleSimon

    SimpleSimon Hall Of Fame

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    Jan 15, 2004
    I really do NOT like a 120 case temp. That means the insides are even hotter, and even though chips can be spec'd to work at those temperatures, it's not healthy for them.

    My 921 is actually COOL to the touch. My 501 gets warm, but certainly under 100.

    My Sony A/V receiver used to run very hot until I gave it some airflow and it's now back down around room termperature.

    I use an open cabinet. Ain't the prettiest stack around, but I don't have to worry about WAF. :D

    Paying attention to such things may be why my electronics regularly last for 20 years. ;)
     
  18. JD Robinson

    JD Robinson Mentor

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    Nov 13, 2004
    No kidding. Just because E* invested in harsh-environment ICs inside the 921 :lol: doesn't mean that the heat coming off a unit that hot isn't bad for everything else around it.

    skassan, you might be surprised how much a simple louvered hole in the top of your center will do for you, if there's not already one there. Convection will draw more air through the hotter it gets in there.
     
  19. SimpleSimon

    SimpleSimon Hall Of Fame

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    Jan 15, 2004
    Yeah right - E* wouldn't spend one penny more than they absolutely have to - even on their so-called "flagship" box. :mad:
     
  20. ClaudeR

    ClaudeR Godfather

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    Dec 6, 2003
    I am thinking of installing it on some form of shelf in my crawlspace (I don't have a basement), but there is a very high humidity. The temperature is certainly more constant. Any comments or suggestions?

    I know the wife will not allow the unit in the living room due to the noise factor. She always falls asleep on the couch about 6 feet from the TV stand. I had to return a Tivo due to hard drive noise, but at least the 921 has a UHF remote. Also had to remove a 1KVA UPS, because it buzzed a little. The less noise the better.
     

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