Thermal switch/control for 12v cooling fan?

mikea

mikea

Touchdown! Greaser!
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iWin
Hey Lance!

I figured out that my my TiVo Premiere is overheating. It goes from 35C at idle to 36C and 37C under load of a inbound transfer. It was locking up and rebooting.

I put a small desktop fan behind it and put it on an old cheapie USB powered laptop cooler tray with fans. It's holding at 36C now as I torture it.

I have a better laptop cooler on order.

What I'd like it add a thermal switch that kicks in the 12V fans at 36C and shuts off at 35C. (I'd wire it into the USB cable.) I have a disk enclosure that comes with some kind of thermal switch wired in with the fan. Do you know what that is and where to get them? It's a tiny horseshoe-shaped device not much bigger than the wire that you thermal tape to the hard drive.

Ideally I'd like a speed control but I'll settle for on/off for now.

These guys have such for PC cases, even fans with thermal probes. I guess I could make my own mount for PC fans or replace the fans in a laptop cooler.

http://www.coolerguys.com/searchres...olled+fan&x=0&y=0&catalog=yhst-24067115789173

http://www.coolerguys.com/840556086611.html

Ok, this thing
http://www.coolerguys.com/840556090885.html

Any ideas?
 
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Where are you measuring this? 37C isn't that bad..Interesting that a simple 2C decrease makes it stable.
 
jesse said:
Where are you measuring this? 37C isn't that bad..Interesting that a simple 2C decrease makes it stable.
Click to expand...

It's what the TiVo reports in its status information. Who knows where it's measured. Somewhere on the circuit board.

When it started freezing up and it was at 37C I managed to position my desk fan to blow in opposite the fan that blows out. Got it down to 33C, which is a low I'd never seen.

I'm doing backflips.



Then 15 minutes later it froze and crashed again. :incazzato:

My best guess now is to let it cool down between inbound file transfers which cause this.

I had just put in a new WD 2TB AV hard drive which may be adding the heat or be the heat sensitive part. Aren't there hard drive heat sinks? I don't think there's space in there for any hardware around it. I think I'm looking at adding a fan. Who knows.
 
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Not sure where Tivo is measuring it but there is nothing inside that machine that shouldn't be able to tolerate 37C. That's pretty damn cool.
 
mikea said:
Hey Lance!

I figured out that my my TiVo Premiere is overheating. It goes from 35C at idle to 36C and 37C under load of a inbound transfer. It was locking up and rebooting.

I put a small desktop fan behind it and put it on an old cheapie USB powered laptop cooler tray with fans. It's holding at 36C now as I torture it.

I have a better laptop cooler on order.

What I'd like it add a thermal switch that kicks in the 12V fans at 36C and shuts off at 35C. (I'd wire it into the USB cable.) I have a disk enclosure that comes with some kind of thermal switch wired in with the fan. Do you know what that is and where to get them? It's a tiny horseshoe-shaped device not much bigger than the wire that you thermal tape to the hard drive.
Click to expand...

Mike, do you have an infrared temperature sensor you can use to independently verify temperatures of particular spots within the box?

35C working to 37C non-working is a very tight range.

If they went with commercial grade components (probably, because the box sits in people's living rooms), they'll operate from 0C to +70C ambient air temp, whereas industrial grade parts will operate from -40C to +85C.

Room temp is about 21-23C, so a 10C rise inside the box isn't all that bad of a change under operating conditions.

But that doesn't speak to die temperatures and localized hotspots, which could cause instability. That's where the IR gun comes in handy. Do any of the ICs have heatsinks? Those would be my targets.

mikea said:
Ideally I'd like a speed control but I'll settle for on/off for now.
Click to expand...

You're gonna need a temp sensor fed into a PWM fan controller for that. I don't know if there are any self-contained temp sensors that can give you an on/off indication with that narrow of a range.
 
You just need a new fan and not switch. Unfortunately I do not have experience with Premiere. I have a Series 2 with 70 mm fan.
 
mikea said:
I had just put in a new WD 2TB AV hard drive which may be adding the heat or be the heat sensitive part. Aren't there hard drive heat sinks? I don't think there's space in there for any hardware around it. I think I'm looking at adding a fan. Who knows.
Click to expand...

The quickest check would be to put the old hard drive back in there and see what happens. From the link I posted before, the scribd doc shows the video decoder chip, its RAM, and one of the BRCM's DDR RAM chips (#3) all live under that hard drive and its heat. Perhaps those are what you're really cooling, and not necessarily the main processor itself.

What are the model numbers on the old/new hard drives?

Edit: you didn't buy this one, did you? It gets shart reviews on Newegg. The datasheet says operating temp is 0 to 60C.
 
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mikea said:
Hey Lance!

I figured out that my my TiVo Premiere is overheating. It goes from 35C at idle to 36C and 37C under load of a inbound transfer. It was locking up and rebooting.

I put a small desktop fan behind it and put it on an old cheapie USB powered laptop cooler tray with fans. It's holding at 36C now as I torture it.

I have a better laptop cooler on order.

What I'd like it add a thermal switch that kicks in the 12V fans at 36C and shuts off at 35C. (I'd wire it into the USB cable.) I have a disk enclosure that comes with some kind of thermal switch wired in with the fan. Do you know what that is and where to get them? It's a tiny horseshoe-shaped device not much bigger than the wire that you thermal tape to the hard drive.

Ideally I'd like a speed control but I'll settle for on/off for now.

These guys have such for PC cases, even fans with thermal probes. I guess I could make my own mount for PC fans or replace the fans in a laptop cooler.

http://www.coolerguys.com/searchres...olled+fan&x=0&y=0&catalog=yhst-24067115789173

http://www.coolerguys.com/840556086611.html

Ok, this thing
http://www.coolerguys.com/840556090885.html

Any ideas?
Click to expand...
I'd go with one or two of the largest fans in your first link. I see no reason to try for 1° accuracy either. The device in the second link requires +5v in addition to the 12v for the fan which will increase the cost.
 
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