# Temperature Issues



## skassan (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?


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## ClaudeR (Dec 7, 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.


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## JD Robinson (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?


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## Jim_R (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.


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## ClaudeR (Dec 7, 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.


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## ClaudeR (Dec 7, 2003)

JD Robinson said:


> On the other side of the coin, so long as Dish is willing to replace it, whadda you care?


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.


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## bytre (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.


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## JD Robinson (Nov 13, 2004)

ClaudeR said:


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


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... )


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## Jacob S (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.


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## David_Levin (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.


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## deweybrunner (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.


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## skassan (Jan 10, 2004)

ClaudeR said:


> 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.


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



David_Levin said:


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


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.


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## David_Levin (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)


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## skassan (Jan 10, 2004)

Jim_R said:


> 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.


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?


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## boylehome (Jul 16, 2004)

skassan said:


> 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?


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.


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## FaxMan (Oct 14, 2003)

Mine is also enclosed in a cabinet along with my other components:

http://gallery.avsforum.com/showgallery.php?cat=500&ppuser=7428023

I got some fans and a temperature sensitive switch from www.markertek.com to provide cool air flow for both the AV gear and the RP-LCD TV.

I really like the temp switch because I (and my family) don't have to remember to turn it on/off.


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## SimpleSimon (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. 

Paying attention to such things may be why my electronics regularly last for 20 years.


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## JD Robinson (Nov 13, 2004)

SimpleSimon said:


> I really do NOT like a 120 case temp.


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.


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## SimpleSimon (Jan 15, 2004)

JD Robinson said:


> ... Just because E* invested in harsh-environment ICs inside the 921 :lol: ...


Yeah right - E* wouldn't spend one penny more than they absolutely have to - even on their so-called "flagship" box.


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## ClaudeR (Dec 7, 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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## boylehome (Jul 16, 2004)

ClaudeR said:


> 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.


Unless you can remove the humidity, don't risk it. Moisture is very bad for electronics, unless the electronic device is made for moisture. The 921 is not one of those devices.


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## TonyB (Jul 5, 2004)

boylehome said:


> Unless you can remove the humidity, don't risk it. Moisture is very bad for electronics, unless the electronic device is made for moisture. The 921 is not one of those devices.


I worked in the semiconductor industry for many years and whet you should be aware of before getting all "hot and bothered" (pardon the pun) about temperatures is:
1. Semiconductors like integrated circuits are all spec'ed and tested to work WITHIN specs between 0 and 70 degrees C. Military ones are a much wider range or course. We can discount the zero degrees end since you are not likely to keep your living room below freezing!. 70 degrees C is 158 degrees F. So unless your circuit boards are up around 140 to 150 degrees there should not be a problem. As for the effect on life, the degrading effects (there are many) for integrated circuits doubles in effect every 8 degrees C. At the max temp of 158 degrees F, the expected lifetime is typically greater than 10 years, and since none of us expect to still be using the 921 in 2014 there should be no effect.

As for humidity, specs are available in most user manuals. You just basically need to avoid "fog" or anything close to 100% humidity. And don't forget, humidity is a function of temperature, so if the unit heats up above surrounding areas, so even at 100% humidity at 70 degrees F it would be a much lower humidity at 100 degrees F (temp inside the unit).

In general, if you can touch the unit without basically getting burned, then its OK. Hot water straight from the hot water tank at home is usually about 120 to 130 degees. Generally a person cannot touch anything above about 120 degrees F and keep it there. So if you can touch the smart card and not pull your hand away then it should be OK.


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## pculley (Dec 23, 2003)

Occasionally the user manual can come in handy, here is a quote from it;
"• Do not place the receiver in an enclosure such as a cabinet without proper
ventilation.
• Do not install the receiver in any area where the temperature can be less than 40°F or more than 113°F.
• Do not stack the receiver on top of or below other electronic devices."

While Most semiconductors have fairly wide temp limits (0-70 C was mentioned), not all do. Modern processors are often limited to a case temp of about 50C. And that is a case temp, not the air temp around it. The air needs to be quite a bit cooler to adequately carry away the heat. The 921 uses a fan to assist in this, but if the air temp that the fan sucks in is too high, the internal temps will exceed operating specs.

So the important thing is to make sure that the air that is near the vent holes is reasonable temp. If putting in a cabinet, make sure that there is a way for air to enter and exit the cabinet in volume, this generally means large openings in front and back, or a fan to pull air out so that air can enter the cracks around the doors.


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## Jim_R (Feb 13, 2004)

skassan said:


> 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?


Scott,

If it were me, I'd put a fan and some air holes in the sides of that entertainment center. It might just be me, but those temps (85 ambient, 105 case) sound too high. I'd suggest doing as boylehome did, radio shack fan pointed outward, vent holes on the opposite side of the e-center, with pulling an airlow flow across the 921 in mind.


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