# Tivo cooling project / Quiet Tivo



## lasitter (Oct 27, 2010)

I've just had my first noisy fan trouble after a little more than a year, and while the cooling threads here have been helpful, I need a bit more information for a cooling project I'm interested for my Premiere XL.

It was easy enough to remove the fan, blast it with compressed air and lubricate it from the access plug, but I know that one day it will be buzzing loudly again.

Fans in the 50x50x25 size are quite rare, and that thickness is important to generating the right static pressure for the case.

The stock fan is the COFAN F-5025L-12F, and for a fan that is so expensive, it REALLY sucks, and not just in terms of reliability. Here are the stats I found on one site:


5025L12V
Amp:........0.10
W:...........1.20
RPM:........3500
CFM:.......12.26 
H2O:.........0.084
dBA:.........22.1

I'm researching other fans that I've seen mentioned in various threads here, but for my cooling upgrade project, there is some other technical data I'd like to have.

When "system information" reports the temperature, exactly where is that measured?

Is it an ambient temperature?

Does it monitor the CPU temperature separately?

It says my case temp right now of 34c is "normal". 

Has anyone seen the temperature response curve that the Tivo uses for spinning up the fan when things get warmer?

I have a lot of ideas about how to keep critical components cooler and happy, but don't know what the system monitors (S.M.A.R.T. for the drive?) and which are most failure prone over time as a result of high temperatures.

I'll share my cooling ideas later, but for now I'll just say they don't seem to have been contemplated much on the forum so far.


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## lasitter (Oct 27, 2010)

Apparently the new XL4 series draw much less power (26 watts max) than my current Premiere XL.

Does anyone know the maximum peak output of the power supply for units like the XL / XL4? I suspect that they could produce temporary bursts of power that were higher, and that sort of info would be useful in selecting fans and fan controllers.


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## stevel (Aug 23, 2000)

Traditionally, the temperature sensor has been part of the power supply. That may have changed in more recent models. I doubt the CPU temperature is measured independently. The hard drive probably contributes more to the heat.

There have been a lot of threads over the past 12 years or so on cooling TiVos. Yes, 34c is a normal temperature and if that's what yours is running I would not spend any effort to try to lower it. All of the components are perfectly happy at that temp.

Typically, you get better results by improving the circulation of air surrounding the TiVo than in trying to 1+ the internal cooling.


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## lasitter (Oct 27, 2010)

stevel: Thanks for responding.

34c is a good temp for lots of computers, but it's winter in Rhode Island now and ambient temps change.

The circulation around the device is a valid point, but I've already got that covered.

My experience with electronics is that they last longer if well cooled. Tivo only has to focus on getting things thru the warranty period.

I like knowing which chips / components tend to get too hot, because heatsinks can work wonders. I have small, self adhesive copper heatsinks that have served me well on computer video adapters. The same heatsinks would work well at improving heat dissipation from the hard drive. I'm not at all impressed by the lone aluminum heatsink. I could fit a copper one that would do a much better job.

Improving the cooling is entirely consistent with getting the most out of hardware that has a lifetime service commitment attached.

Temperature control inside computer cases is something I've been focused on for many years, and once you pull the cover off a Tivo box, it's obvious that you're just looking at a specialized computer.

I've spent a fair number of hours over the past week searching threads about Tivo cooling, and while I found lots of "maybe" fan model proposals, I ask the questions I have because I didn't find what I needed. If you have any of the tech info about temperature / fan response curves, great. "Don't worry about it" doesn't help me so much.


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## stevel (Aug 23, 2000)

I've never seen such data. All of the TiVos I've worked on run the fan at constant speeds. Some were better designs than others (the Series 1 DTiVos were particularly awful.)

If it makes you happy to fiddle in this area, don't let me stop you. I assume you already own an IR thermometer that you can use to make your own measurements. My experience is that most of the heat in the enclosure comes from the hard drive and that the electronic components barely rise above ambient. That said, my experience inside TiVos ended with the HR10-250 so I have no idea what the Series 3 and 4 boxes are like. Many of us have TiVos that have run for five, six, even ten years. The major issue with cooling has been failed fans, not "need better" fans.


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## lillevig (Dec 7, 2010)

I think you are worrying too much. As was pointed out, there are still S1 boxes merrily working away and the two I most recently sold typically ran in the high 30's. I just checked my S2 box and it was at 38. My P4-lite is at 40. I had an S2DT box that typically ran in the 40's and that was still in the normal range.


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## unitron (Apr 28, 2006)

stevel said:


> Traditionally, the temperature sensor has been part of the power supply...


The power supply may have a temperature sensor of its own, for its own protection, but has no way to communicate information from it to the motherboard. It doesn't send out data, just DC current.


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## lrhorer (Aug 31, 2003)

unitron said:


> The power supply may have a temperature sensor of its own, for its own protection, but has no way to communicate information from it to the motherboard. It doesn't send out data, just DC current.


Yeah, I was going to make that point. Almost all modern CPUs have an internal temperature sensor built in, and so do most chipsets. The reported temperature is probably the CPU temp, or maybe the Northbridge.


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## lasitter (Oct 27, 2010)

While not about the Tivo specifically, this article reflects a lot of what I've come to believe about giving electronic components a long, happy life ...

Thermal Management Part 1: How Hot Is Too Hot?



> In our world of electronic product design, we live by this rule of thumb: For every 10 degrees Centigrade rise in temperature, the average reliability is decreased by 50 percent. Or, from the quality assurance department's point of view, if we can lower the temperature by 10 degrees, we'll double the reliability. In other words, we will double the expected life within any predictable failure rate. Another way to look at this, for those interested in buying products with good MTBF (meantime between failures) ratings, is that MTBF will, on average, double if the operating temperature is lowered 10 degrees.


If you read the piece I think you'll get an idea about answering the obvious question "10 degrees relative to what?"


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## jrtroo (Feb 4, 2008)

I don't expect to be using my tivo over the next 300 years. I'm good as is!


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## lasitter (Oct 27, 2010)

jrtroo: What I'm interested in is not for everyone, but it does make a certain amount of economic sense.

If you paid the monthly guide max (19.99?), then you'd cover the cost of the $499 lifetime in 25 months.

If, however, you could somehow figure out how to make the device last 10 years (120 months), your guide-cost-per-month would fall to as little as $4.16 per month ($499/120). 

I'm in the process of upgrading an otherwise still working computer right now because an expensive add-in RAID controller failed after seven years, so with the right cooling, 10 years is not out of the question.

I'll be getting my Premiere XL4 this week, and with my existing Premiere XL, the six combined tuners should cover my viewing needs for a very long time. I'm just trying to make the most of my investment as I suspect I don't want to find out what Tivo charges for a mainboard replacement.

In 300 years I'll be dead and everything I own will be irrelevant and long gone too. Digital high def (and I) might be around for another 10 years, and Tivo has already been around since '99, so that's a time frame I can deal with.


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## stevel (Aug 23, 2000)

But in 300 years, the TiVo Mini might be released!


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## jrtroo (Feb 4, 2008)

Tivos have two primary points of failure, and heat in a well ventilated area has not been a contributing factor. So they should last a good long time without extra cooling (there are reports of s1 units in the wild, and many many s2s and s3s). Technology is more likely to outpace their usefulness to the original owner. 

I hope to not have to wait even 300 days for the Mini!

Long life is great- I count on is through lifetime service. Bad for Tivo's bottom line as I'm now basically a free rider.

You are on an interesting path, no doubt, but its certainly not for everyone.


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## poppagene (Dec 29, 2001)

lasitter said:


> Fans in the 50x50x25 size are quite rare, and that thickness is important to generating the right static pressure for the case.
> 
> The stock fan is the COFAN F-5025L-12F, and for a fan that is so expensive, it REALLY sucks, and not just in terms of reliability.


I'm not convinced that you need a fan that is 25mm. Plenty of 50x50x10 and 50x50x15mm fans could be had much cheaper. AFAIK, the depth of th efan isn't the only factor in generating static pressure and if you look at the specs of all the 50x50x25 fans made by COFAN you'll see a wide varitety for specs on static pressure.

http://www.cofan-usa.com/axial-fans/50x50x25


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## lasitter (Oct 27, 2010)

poppagene: You are right in that there are many alternatives.

One thing I considered is stacking two 10-15 mm counter-rotating fans. If you were really slick, you could go with fan controllers with different response curves for each fan ...

Smart Fan Speed Controller I With Temperature Sensor
Smart Fan Speed Controller II With Temperature Sensor

With a customized response curve, you could have one fan spin up first and then another spin up if things got even hotter.

It would also give you redundancy in the event of a single fan failure.

Of course, this is all from a guy with a Supermicro server case with five regular fans plus the three (triple redundant) PSU fans plus two fans for northbridge/southbridge chips. It would be more but I replaced the video heatsink / fan with a big passive copper heatsink not long ago.

I well realize that the Tivo PSU wouldn't even run the fans in my current server case, but that's part of the fun of figuring out what you can do with what you have ...


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## steve614 (May 1, 2006)

lasitter:

I think you are the first person of which I've read here who cares this much about cooling. (NTTAWWT) 

The copper heatsinks, how would you attach them? Thermal glue?

Like stevel mentions, if you have an IR thermometer you should be able to read the temps of individual components on the motherboard.

You might be the pioneer that figures out an aftermarket cooling system for Tivos that allow you to use a slower/less noisy case fan.
Is there a market for it? I don't know, but it sounds like a fun project.

Keep us aprised of your findings.


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## SNJpage1 (May 25, 2006)

I can see it now an after market liquid cooled Tivo. It probably wouldnt be that hard to build.


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## unitron (Apr 28, 2006)

Use something like this:

http://s429.beta.photobucket.com/us...mages/ASUS P67 SABERTOOTH 50-60mm Fan Adapter

which was discussed here:

http://www.overclock.net/t/1148238/wanted-line-drawing-for-50mm-to-60mm-fan-adapter

and mount a larger fan on the outside of the back panel.

You could even get a wall wart and power it separately from the TiVo supply.

If you really want to get crazy (and have unlimited "all my mansions have car elevators, life wouldn't be worth living otherwise" funds), have someone design something similar that includes a piggy back plug into the TiVo's AC socket as well that also incorporates what would otherwise be in the wall wart.

Of course it may take a while to get UL certification.


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## stevel (Aug 23, 2000)

I think lasitter needs to consider oil immersion.


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## unitron (Apr 28, 2006)

stevel said:


> I think lasitter needs to consider oil immersion.


How long should he stay under?


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## unitron (Apr 28, 2006)

stevel said:


> I think lasitter needs to consider oil immersion.


Maybe in his church they'll let him get by with just sprinkling.


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## MeInDallas (Jul 31, 2011)

unitron said:


> and mount a larger fan on the outside of the back panel.


I never thought of that


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## MeInDallas (Jul 31, 2011)

Oh and by the way, I used this as a replacement fan for the Premiere and it works really well and is completely silent and only $5. Its the same size as the original as well. It has 3 wires, but you just use the black and red wires and its fine.

http://www.amazon.com/IPCQUEEN-50x50x25-Bearing-connector-fan-ipc-505025/dp/B004H6GZCU/ref=wl_it_dp_o_pC_nS_nC?ie=UTF8&colid=3E335VWVNRJEK&coliid=I1SXUUXCG2RIEI

The picture shown there is not the correct one for some reason.


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## slowbiscuit (Sep 19, 2006)

This has to go down as one of the best OCD threads ever.


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## lasitter (Oct 27, 2010)

unitron said:


> Use something like this: (50->60mm) and mount a larger fan on the outside of the back panel.


I was looking for a 50->40 fan adapter (would mount internally), but 50mm is such an oddball size there's sadly nothing for it.

As to external powering, one of the things I'd love to know is what kind of safety margin the Tivo power supply already has. It dissipates 26 watts when it's working, but and it make a few watts to spare? If so, the replacement fan could run on the standard power supply.


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## lasitter (Oct 27, 2010)

steve614 said:


> I think you are the first person of which I've read here who cares this much about cooling. (NTTAWWT)


It's the computer server background! 


steve614 said:


> The copper heatsinks, how would you attach them? Thermal glue?


What I've ordered will be using 3M 8815 Thermal Tape ...

Enzotech BMR-C1 VGA Cooler
Enzotech MOS-C1 C1100 Forged Copper Heatsinks
Enzotech MOS-C10 C1100 Forged Copper Heatsinks only
Enzotech CNB-R1 Forged C110 Pure Copper Heatsinks only

I'll probably use a physical mount for the big heatsink on the Broadcom chip.

Two of the four Micron 9WG27 128MB DDR2-800 system memory chips are apparently mounted on the bottom side of the board.

Don't know what you could do to cool them better ...

I also don't know if there's any room under the HDD for the chips under there.

A lot will depend on the temperature returned by the laser meter.



steve614 said:


> Like stevel mentions, if you have an IR thermometer you should be able to read the temps of individual components on the motherboard.


I do have one, and it's a fun gadget. I definitely plan to used one ...



steve614 said:


> You might be the pioneer that figures out an aftermarket cooling system for Tivos that allow you to use a slower/less noisy case fan.
> 
> Is there a market for it? I don't know, but it sounds like a fun project.
> 
> Keep us apprised of your findings.


Will do.


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## lasitter (Oct 27, 2010)

lrhorer said:


> Yeah, I was going to make that point. Almost all modern CPUs have an internal temperature sensor built in, and so do most chipsets. The reported temperature is probably the CPU temp, or maybe the Northbridge.


Most CPUs also throttle back if they start getting to hot. I wonder how quickly the fan spins up to prevent that. Any throttling to control heat could show up in system performance.


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## lasitter (Oct 27, 2010)

MeInDallas said:


> Oh and by the way, I used this as a replacement fan for the Premiere and it works really well and is completely silent and only $5. Its the same size as the original as well. It has 3 wires, but you just use the black and red wires and its fine.
> 
> IPCQUEEN 12 V DC 50x50x25 mm Ball Bearing Fan


This is awesome. Don't know how I overlooked it. Think I'll have to try this out!


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## unitron (Apr 28, 2006)

lasitter said:


> I was looking for a 50->40 fan adapter (would mount internally), but 50mm is such an oddball size there's sadly nothing for it...


Which is why the guy I linked to had to go the custom fabrication route.

But I was thinking putting the fan on the outside would let you use a bigger, slower, quieter fan.

It would also be an interesting experiment to see if one could mount outside and blow in (which would allow use of a snap-on filter which could be periodically cleaned) and still get the needed cooling.



lasitter said:


> ...
> As to external powering, one of the things I'd love to know is what kind of safety margin the Tivo power supply already has. It dissipates 26 watts when it's working, but and it make a few watts to spare? If so, the replacement fan could run on the standard power supply.


Using internal power for something externally mounted introduces not only "does the supply have the capacity" but the "how to run the wire from inside to outside", and a wall wart solves both problems.

Any fan you could fit where the original internal is mounted probably isn't going to bring the TiVo power supply to its knees.


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## lasitter (Oct 27, 2010)

unitron said:


> Any fan you could fit where the original internal is mounted probably isn't going to bring the TiVo power supply to its knees.


I feel like an idiot for not noticing this before ...










If you bring the picture up to maximum size, it gives you the power supply spec right there on the PCB ...

42.48w

That's lots more than the total unit max draw of 26w I'd seen quoted elsewhere.

I just got in three of the IP Queen fans, and they look very similar to the COFAN. If these specs are right, I should be in business ...

50 x 50 x 25 mm Ball Bearing 
12VDC Operation Voltage: 6.0~13.8 
VDC Rated Current : 0.25A 
Rated Speed : 2600 +/- 10% RPM 
Air Flow : 28.00 CFM 
Static Pressure : 3.2 mmH2O 
Noise Level : 26 dBA 
Weight : 44g

Double the airflow at 2600 vs 3500 RPM?? We'll see.


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## scn101 (Aug 13, 2013)

I bought a replacement Cofan and found it still quite noisy. If I hold the fan in my hand it is fairly quiet but once attached to the Premiere there's kind of a roaring noise. I tried using O-rings on the screws to isolate it from the chassis but that only helped a bit.

So how quiet are the IP Queen fans? Better than the Cofan, or the same?

Thanks.


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## MeInDallas (Jul 31, 2011)

The IPC Queen one is way quieter for me. Maybe because its ball bearing, and the Cofan ones are sleeve bearing, not sure.


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## scn101 (Aug 13, 2013)

Ok, thanks for the very speedy reply! I ordered one and will report back.



MeInDallas said:


> The IPC Queen one is way quieter for me. Maybe because its ball bearing, and the Cofan ones are sleeve bearing, not sure.


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## MeInDallas (Jul 31, 2011)

Oh and when you get it, if you use the Tivo screws, screw them in really REALLY slow, or just use the ones that come with the fan. The first one I got, I cracked the side of it because the Tivo screws are so fat


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## scn101 (Aug 13, 2013)

I received the IPC Queen fan and unfortunately I found it to be louder than the Cofan.

I did find a way to make the Cofan quieter. Someone suggested removing the label on the Cofan, removing the rubber plug, and adding an oil/grease mix. I did that but observed no real change to its volume.

Then I decided to push the fan blades off their spindle. Using both thumbs through the housing the blade assembly slid off revealing the sleeve bearing. I oiled and greased it, ensuring the oil went between the sleeve bearing and the spindle. I then reassembled it by pushing the blade assembly back on the bearing and mounted it back into the Tivo using O-rings on both sides of the screws to isolate the fan from the box as much as possible.

Now the Premiere is quiet. I can still hear the fan moving air but no other obnoxious fan sounds so that's good enough.

BTW, I tried pushing the fan assembly off the IPC Queen to lube it as well but it simply broke,


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## unitron (Apr 28, 2006)

When actually removing the blade and shaft assembly from one of those fans, you have to remove the label on the part that doesn't turn, remove the plug, if any, and then there will be a little C ring or O ring type washer that snaps into a groove on the shaft, and it needs to be carefully removed and will jump across the room and disappear forever if you give it the chance.

Once you get that off, you should be able to pull the blade hub and shaft assembly out of the bearing easily.

There should be no reason to remove the shaft from the blade hub as they don't turn independently of each other.

You might need a Q-tip and some denatured alcohol or lighter fluid to remove the old lubricant to see that little clip in the first place.


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