Using computer fans to cool a plasma TV cabinet?

Noted, there are a few other forums perhaps more dedicated to this topic, but this is my favourite group by far, so I thought I'd start here. Besides, from what I've read on these other forums, the geek- factor plays a major role and, in most threads, assumes that every set- up, however small, should measure up to your typical digital, multi- plex, cinema experience!
This just ain't the case for your average Jo!
I'm an average Jo, and so is my pal/colleague/client. We are neighbours, running our own, separate, businesses, in the construction industry. Possessing different trade skills, between us, we often join forces, to provide each other's clients, with a greater range of services, readily at hand.
We also do a bit for each other, on our own houses, which is the case right now...!
He's built an enclosure for his flat-screen plasma TV and has asked me to do the electrical work, so he can power everything up, within the false chimney breast he's made, from timber studding. Nothing exceptional there, as you can imagine. There's a skirting-board-level, twin socket nearby that's on the local ring-main and its a small matter to extend this into the timber enclosure, and add the necessary outlets, where required, once I'd got from him how many he needed.
However, knowing how clueless he is, when it comes to electrics, I put a few questions to him, one of which concerned the opinion, held by the manufacturers of his particular model Plasma, with regards to it being encased in a cabinet and continuing to function normally, without over-heating!
Next thing I know, he's handing me 2 small electric fans he'd bought from Maplins, following the advice of someone or other. With no idea about their needing a 12V DC power supply (let alone a means by which to control their activation/deactivation, according to TV usage and/or excessively high temperature levels) he's then asking me to hook 'em up as part of the installation!
To quickly conclude an already-long post... We spoke. I explained. He eventually understood. I propose the following solution:- One fan mounted at top-left-hand-side of false chimney, hidden by grille - exhaust. Other fan mounted at bottom-right-hand-side of false chimney, hidden by grille - intake. Both fans powered by 12V DC lighting transformers. Transformers connected to mini-jb Circuit activated by under-tile heating thermostat using under-tile probe mounted on wall behind TV. 24-hour timer governs thermostat operational periods. FSU protects and isolates complete circuit.
Alternatively, I can go the computer component route, as described here... http://www.avforums.com/forums/showthread.php?t@1717
Opinions on a post-card please!! Or just reply to this thread :)
thanks, d.
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deano wrote:

Most lighting transformers have an AC output...

I would have thought the temperature sensitive approach (common in the better PC setups) would be a better starting point if you decide you need active cooling.
Have a look at :
http://www.quietpc.com/gb-en-gbp/products
However one (particularly appropriately named) passive cooling method is the chimney effect. When you have a long tallish enclosure such as you describe, you should get a reasonable air flow through it just using convection cooling. An air admittance vent low down, and an exhaust high up will probably draw a fair amount of air through once the space heats up. You could even experiment with venting the exhaust into the chimney stack (assuming its not used for a fire etc). A posh solution may be to have the top vents switchable - up the chimney in the summer, and back into the room in the winter.
--
Cheers,

John.

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deano wrote:

I didn't know which bit to quote as there was so much!
Convection cooling will be fine - just make sure there is a grille above and below the panel.
Alternatively, just leave a small shadow gap around the panel like I did:-
http://gallery.mac.com/loopylup#100011/IMG_0566
I really wouldn't go down the router of fans - it's both unnecessary and risky should they fail (which they will).
Steve
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deano wrote: > Massive Snippage
I didn't know which bit to quote as there was so much!
Convection cooling will be fine - just make sure there is a grille above and below the panel.
Alternatively, just leave a small shadow gap around the panel like I did:-
http://gallery.mac.com/loopylup#100011/IMG_0566
I really wouldn't go down the route of fans - it's both unnecessary and risky should they fail (which they will).
Steve
(I posted my original reply via Google Groups which I know a lot of people block - so apologies for the double post)
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On Tue, 29 Jul 2008 09:04:38 +0100, Steve Lupton wrote:

But with a baffle of some sort above the vent to direct the rising warm air out through it.

Some scipt ridden propritary thing, what wrong with just posting a link to the image file FFS?

So why bother posting via Google Groups in the first place?
--
Cheers
Dave.




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Dave Liquorice wrote:

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Dave Liquorice wrote:

Agreed
Because it was quick and easy, and the rest of the pictures in the gallery might have been of interest to the original poster.
Did you get out of the wrong side of the bed or something?
Here's the bloody link:-
http://gallery.mac.com/loopylup/100011/IMG_0566/web.jpg

I don't know why I am bothering to explain myself...
Habit... I'm not normally in front of a machine that has NNTP access during the day. I posted from Google Groups and then remembered about people like you...
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I couldn't agree less ...
Most manufacturers, having experimented with taking the forced air cooling out of plasma TV sets, have started putting it back in. Plasmas run very hot, and some of the internal components are running close to their limits temperature-wise, in normal open ventilated conditions. My feeling is that if you enclose it in this way, you are likely to have problems not too far down the line - and you don't want to know the costs of replacing say a destroyed Y-sustain board or power supply ...
Personally, I would use 240v AC fans with roller bearings. You can also get them with sleeve bearings, but they are not so quiet in the first place, or quite so long lived noise-wise. I would absolutely refute the contention that using these is risky in that they will fail. I run PCs in my business 24/7, and have never had any decent quality mains voltage one, fail.
As far as switching the fans goes, a few months back, Elektor magazine published a design for a 'through' power box, that senses when current is being drawn by some main item, such as a computer, and then switches on one or more additional sockets to power up peripherals such as a printer or whatever. I'm pretty sure that I've seen these available commercially somewhere - possibly in a computer shop in the accessories ?? Seems to me that would be the route to go down so that your friend could not forget to turn them on. If he is having a full home cinema setup, with a separate AV amp, many of these have a switched mains outlet on the back to feed say a separate tuner, so that would be another satisfactory way of providing switched power to fans.
Either way, if you want the TV to be long-lived, along with any other equipment that may be getting put in the same enclosure (sat box, DVD / HD recorder, AV amp etc) you need to make sure that there is a good supply of cool air from near floor level, and that the heated air is properly exhausted from above the equipment. Trust me, I mend this stuff for a living, and probably about the most common failures that I see in home cinema equipment, are heat related due to the owners 'building the kit in' ...
Arfa
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Arfa Daily wrote:

A build-in too far? :-)
Fire damages home cinema 3:39pm Monday 28th July 2008
FIRE crews were called to tackle a blaze this morning after a home cinema caught fire.
Firefighters received the call shortly after 9.30am when an out-building of a house in Amersham Road, Beaconsfield, caught fire.
The first floor and roof space of the two storey building, which contained a home entertainment system, were damaged. advertisement
Fraser Pearson, communications manager for Buckinghamshire Fire and Rescue, said: "They managed to save quite a bit of the roof, but most significantly they prevented the fire from spreading to the main building."
<http://www.bucksfreepress.co.uk/news/localnews/display.var.2411315.0.fire_damages_home_cinema.php
(There is nothing more on the site than a few comments by the usual suspects for the BFP.)
--
Rod

Hypothyroidism is a seriously debilitating condition with an insidious
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Arfa Daily wrote:

A lot depends on the panel though. The Panasonic PS and PH range run very cool compared to a lot of other panels.
If a panel fails within an unreasonable time period, I would be looking at exercising my rights under the sale of goods act rather than worrying about the cost of the repair.

My point is that it is completely unnecessary. If the panels needed external fans to keep cool, they would come in the box with installation instructions.
They don't - therefore it is not necessary... I wouldn't for one minute recommend building them into a solid unventilated enclosure, but as long as there is a free air flow around the panel that is more than enough.

All good points and very logical, but I still don't see the point!

Don't misunderstand me - I am not saying ventilation is not necessary. I'm just saying that I don't think a PDP needs forced ventilation unless installed in a most unusual way
If you look at the other images in my gallery, you will see that I have my equipment in a hole in the wall and the projector is flush mounted inside a stud wall.
Both those compartments have extraction in them as it would have been insane not to do so - I just did not feel it necessary for the Plasma.
Steve
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What's your view of the current best of breed in plasma and LCD TVs in the mid range sizes (i.e. 71 to 85cm, not as large as 106cm)? Is there a consistent good performing manufacturer in terms of picture quality and reliability?
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The Panasonic one just before the current Viera one was a very good performer, and all of the Pioneers have been good, if a little expensive. If you are intending watching regular resolution TV transmissions on it - remember that there is not going to be much in the way of HD on Freeview ever, by the looks of it - when you go looking at them in-store, ask to see a standard resolution picture being displayed on any you like the look of. Most retailers feed them with HD from a Blu Ray player, with a demo disc in, and of course, they look stunning in this native-mode resolution. However, ask the set to display a standard resolution picture, and you might be disappointed with the results. Many produce pictures which have significant motion blur, and sometimes, motion artifacts.
And to Steve. Building a panel into any kind of enclosure is not a standard installation, which is why the units don't come with external fans and instructions. They are designed to be placed either on a floor stand, or on a wall mounted surface bracket, either of which ensures that there is a free-flow of air around the whole unit. As far as failure within a reasonable time goes, I rather think that if you had such, and called out the suppliers under the guarantee, they might just reject your claim, sale of goods act, or not. I can see from your picture how you believe that your particular installation fulfils the criteria of necessary ventilation, but from the description of what this poster seems to be doing, I would question that temperatures behind the set will remain low enough, particularly during hot weather, to ensure reliability.
Even in your case, unless you are an engineer who understands the internal workings of a plasma TV - or even an LCD TV for that matter - I would suggest that there may well be 'hot-spots' inside your unit that you don't know about, that would not be there if it had totally free air circulation around it.
Given the installation that the OP is proposing, and my daily experience with consumer electronic equipment, I feel that his desire to fit some additional assistance to the cooling, rather than relying entirely on convection, is highly reasonable and responsible. A grille above and below the set is going to be necessary - we are all agreed on that - so you might as well fit a couple of fans behind them for the small additional cost, and convenience of doing it during construction, even if it did ultimately turn out to just be a case of 'belt and braces'.
And it might just get you another couple of years life from the set, after the warranty expires ...
Arfa
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Arfa Daily wrote in
<snip>

Is that also the case with freesat?
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PeterMcC
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Nope. Plenty of bandwidth available for HD transmissions. Actually, I can't really see any reason for Freeview to survive, now Freesat is with us ...
Arfa
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Thanks for that. I'm familiar with seeing poor conversions with projectors.
Do the Pioneer products behave reasonably well with standard pictures?
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Andy Hall wrote in

I'll second that - I'm not sure if it was mentioned in the recent thread on projectors but, IMHO, anything other than native resolution is likely to produce a less than satisfactory image. The resolution and the luminance are the two over-riding factors in specing a projector.
--
PeterMcC
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Better than a lot, yes. Friend of mine has a high-end audio and HC shop, and he only sells Pans and Pioneers for that reason.
Arfa
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wrote:

I'd consider a filter in the air intake as well. One the one hand all the lint will end up in one place, carefully designed to be easy to clean, rather than spread out furring up all the electronics.
OTOH, if filter cleaning is forgotten, and it clogs, you're worse off than before.
Thomas Prufer
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http://www.oneclickpower.com/store /
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and presumptuous desire for a second one."
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wrote:

Yep ! That looks like it would do the job
Arfa
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