Is there a good way to wire fans to turn on with tv?

[davep911]

Is there a good way to wire fans to turn on when the tv does?

Is it better to have fans blowing in at the bottom or blowing out at the top?

[budm]

Re: Is there a good way to wire fans to turn on with tv?

You can use the switched 12V or the switched 24V (I would use the 24V which is typical used for the backlights inverter) but you will need to find out what you have in your TV.

[davep911]

Re: Is there a good way to wire fans to turn on with tv?

Here is my SMPS. I am thinking about using 4 - 12v .18a 80mm fans and maybe speed control

[tibimakai]

Re: Is there a good way to wire fans to turn on with tv?

I'm using for my Onkyo receiver a laptop cooler pad.
I have made a wire with USB connector and plugged it in the USB port of the TV.

[stj]

Re: Is there a good way to wire fans to turn on with tv?

you should use the fans to draw cold air in.
if you put them at the top to suck the hot air out, the air going through the fan heats the bearings and dries out the oil.

[tom66]

Re: Is there a good way to wire fans to turn on with tv?

Not if you use proper fans - Panasonic has used top mounted fans on their plasmas for years, with no problems.

[stj]

Re: Is there a good way to wire fans to turn on with tv?

most people dont use "proper" fans though - they will just read this thread and go buy something from a pc supplier for the price of a couple of beers.

[davep911]

Re: Is there a good way to wire fans to turn on with tv?

If it doesn't really matter if the fans are on top or bottom i will put them on the bottom. I'm surprised I can't find much info on this, my tv can't be the only 1 running 150 deg F. The few examples I have found online were to "rigged" for my liking. I can't find 12v on my SMPS but 15v should be fine as long as I use a fan controller, I'm just worried about load and interference.

[stj]

Re: Is there a good way to wire fans to turn on with tv?

load is low,
interference will be unknown till you try.
but i double it cant be stopped with a choke or a ferite-ring.

[Per Hansson]

Re: Is there a good way to wire fans to turn on with tv?

It would be nice to hook it up to a constant power source, and use a thermistor.
That way the fan only turns on after a while when the TV becomes hot.
And it will cool the TV down even after you turn it off...
Obviously with a potentiometer aswell so you can set a good trip point for when to start the fan...

http://www.electroschematics.com/478...rolled-dc-fan/

[Alastair E]

Re: Is there a good way to wire fans to turn on with tv?

Your average fans are just too damned noisy!

I have used fans in the past, but run them at 5V where they are quiet and get the job done. Ive fitted a few to various plasma sets on hot parts such as the Y-SUS boards etc, the temp of the heatsinks is reduced tremendously, even though they are circulating air that is Inside the case. They dont seem to get cacked up with so much dust either!

Using fans to draw air into or out of the case has its own issues--They block up with dust in a pretty short time with the small grilles usually used.--Check out your average Panasonic plasma fans next time you got one!

[tibimakai]

Re: Is there a good way to wire fans to turn on with tv?

These fans, are pretty good. They don't move a lot of air, but it's enough and they are very quite:
http://www.newegg.com/Product/Produc...82E16835214016

[davep911]

Re: Is there a good way to wire fans to turn on with tv?

Thanks for the suggestions and comments.

It would be nice to hook it up to a constant power source, and use a thermistor.
That way the fan only turns on after a while when the TV becomes hot.
And it will cool the TV down even after you turn it off...
Obviously with a potentiometer aswell so you can set a good trip point for when to start the fan...

http://www.electroschematics.com/478...rolled-dc-fan/

This was my first plan but after looking at a few schematics I decided this would be too time consuming for me to build. After thinking about options and more searching I found these fans that should work well. They come in 80mm also.
http://www.ebay.com/itm/SilenX-Effiz...ht_1682wt_1362

[Per Hansson]

Re: Is there a good way to wire fans to turn on with tv?

Yea fans with built in thermistors are also nice, I have a couple 80mm SilentX fans that I like.
The one you found seems better, it has a long cable for the thermistor (Not that it can't be modded on the one I have of course)

[davep911]

Re: Is there a good way to wire fans to turn on with tv?

I don't know what temp turns the fans on but I figure I can move the thermistor around to adjust it.

[stj]

Re: Is there a good way to wire fans to turn on with tv?

it's not a case of on/off - it changes the speed relative to the temperature.

[davep911]

Re: Is there a good way to wire fans to turn on with tv?

it's not a case of on/off - it changes the speed relative to the temperature.

I understand rpm is relative to temp, I meant I don't know if they turn on at 80 or 100 or another temp but now I just read something that makes me think they come on when they detect a rise in temp.

[stj]

Re: Is there a good way to wire fans to turn on with tv?

no, they will spin enough to move air at room temp
you should be able to get a datasheet with the airflow tables.

[davep911]

Re: Is there a good way to wire fans to turn on with tv?

I can't find any fans that turn on and off based on temp so can anyone here tell me where I can hook to my SMPS without any problems? I don't even know if there is a 12v source and I don't really want to use any resistors on the 15v and I don't want the fans on all the time if the tv is only on around 30% of the time.

[stj]

Re: Is there a good way to wire fans to turn on with tv?

if the 15v is switched with the tv, then use the 15v and put a 7812 regulator and a couple of caps on some stripboard - dont forget to bolt a heatsink on it.

if you want to run them slower use a 7809 or 7808 but it will generate more heat!