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NEC XG Fan Size

580 Views 18 Replies 8 Participants Last post by  Ursa
I'm looking to replace the stock fans in my NEC XG135 with some silent ones. Does anyone know the size / quantity required to perform such a task? I could take the boat anchor off the ceiling and do the count myself but I'd prefer to do it just once when the fans arrive.

This is doable isn't it? Am I crazy?

I know I could build a hush box (and I probably will) but I'd like to try a nip the problem at the source.

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Previous posts indicated that there's not much to be saved by replacing the fans. For the most part they are already very quiet. The noise is mostly from turbulence. A hush box is the best solution if you want significant noise reduction.

There was an excellent thread quite a while back on this. Do a search on "plants" (the title of the thread had that in it).
Ahh,... I suppose I'll just break out the tape measure and go for the hush box then.

Thanks for the info and the link.
Try also a search for "fan mod". Chuck Williams developed one that reduces the fan speed and thus the noise.
I can vouch for the Fan mod. I have it on my XG135 and can barely tell it's on. On mine the noisiest fan was the small 60mm fan that's right in the center under the "top" cover. I was able to quiet that one down by replacing the bearings. The new bearings came from a fan I was going to install but found the feedback wire wasn't compatible with the projector. If you are curious, the 'donor' fan was a ThermalTake - TT 6025A-2b.
Jerry, how difficult was the bearing replacement activity? I did not know these fans were designed for bearing replacement (i.e. thought they were designed as throw-away devices).
This is the first I've heard that a significant quieting can be acheived by replacing the bearings on this particular fan.

Jerry, was the fan problematic prior to your replacing the bearings? or do you think you have upgraded/modded the fan from its stock condition?

Could somone simply clean and grease the bearings?

"Iceman" posted a compact hushbox/ silencer design under a thread called "Sound damping plants" here:

Also, KennyG is credited with another brilliant XG Hushbox design which is posted here: (I understand that it has since been painted!)

I'm in the midst of building one myself adapted from the KennyG design.
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My line of thinking for this whole thing was that back in 1996 (or whenever) NEC probably didn't have access to or care about using the newer "noiseless" fans that are so easy to come by now. Again, I was thinking of killing the problem at the source.

That being said, if turbulence is the culprit, then perhaps the hush box is the way to go. I was planning on fabing up an aluminum shell and lining it with some old acoustic ceiling panels that I had kicking around. I have sort of a weird set-up with the way my projector is mounted but it does facilitate the use of simple aluminum panels for the sides, front and rear of the projector. They’d be easily removed for maintenance and fine tuning (12lb sledge hammer). I’ll take some pics when I get home tonight so you can see what I’m talking about.

Anyway, long story short, perhaps I’ll start with the hush box and see what the noise is like before I start tearing out the NEC fans.

Thanks for the links and the great info guys.
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Jeff, keep in mind that turbulence is a disruptive flow of a moving medium. If the turbulence-function varies to a beneficial conclusion with slowing moving air in the projector, one could counter-offset the need to remove bulk heat by effectively lowernig the air coming into the projector to begin with.

For instance, if you pull 70ºF ambient-room temp air compared to 55ºF 'chilled' air, you could try to determine the lower air-flow (CFM) needed to maintain the same operating temperatures determined in the pre-mod setting. This is exactly what I have thought about (amongst other things).
Maybe I could just hook up one of these to cool the damn thing down. Don't know what the noise would be like!

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Here's a picture of my projector support;


I can easily mount some aluminum side panels to the tubular uprights and build an aluminum box / baffle to cover the rear area. I just need to be careful at the front end and not cover up the IR receiver. The side panels can support a bottom panel to completely enclose the projector. Sadly, there's only about 1" of clearance between the rack and the bottom of the projector at the front.

I'm sure I'll figure something out.
I've considered running cold air from a small refrigertor in a remote room through a small diameter duct---maybe 1 1/2" through the ceiling into a hush box. (I'm in an apartment so ceiling holes can't be too big)

One of my main concerns with this setup is condensation on projector parts as cold air comes into contact with the warm moist air around the pj particularly in the warmer summer months. Anyone ever think this one through?

P.S. Jeff, that is an astonishing collection of gear.
I've often thought it would be kind of neat to run a dryer hose from my projector/HTPC to a bathroom fan mounted on the outside wall of the house. Maybe when I build a house from scratch I can throw in some "central cooling" for all my toys. I should have thought this all through before my last basement renovation was completed.
Last summer I thought about buying a 5200 BTU $119 window AC unit from Home Depot. It came with a 5-year warranty and was a Maytag! I thought I could mount this in a window in the HT's adjoining room and use insulated flex-duct to transport it to the projector.

I also thought about making a cold trap room directly behind the rear wall of the theater. The HT room's rear wall is a wall over a windowed wall. I could have built a 2.5-3' room, used the double-windows for an AC unit, and then quietly drawn upon the chilled air in that room, through PVC pipe, to the projector.

djordan asked
Jerry, was the fan problematic prior to your replacing the bearings? or do you think you have upgraded/modded the fan from its stock condition?
The fan seemed problematic since the scratchy sound it made would vary but was always present.

Jerry, how difficult was the bearing replacement activity? I did not know these fans were designed for bearing replacement (i.e. thought they were designed as throw-away devices).
The bearings aren't molded into the case so they are easily replaceable. You need to pull up the round label, remove the "C" clip that snaps into a groove on the end of the fan shaft, then pull fan blade/shaft out. There are 2 bearings with a spring between them. The bearing close to the fan blade will likely stay on the fan shaft when you pull it out because the spring is pushing it out of the chamber that holds the bearing in place. The other bearing is just pressed into the bottom of chamber so you just need to push it out the same way the fan shaft went when you pulled it out.

The hardest part is getting that "C" clip out without it flying into 'who knows where'. I used a tool that looks like an ice pick and needed 2 so I could pry it open. There are pliers made for this type of clip but I don't know if they go down to that size
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Great info Jerry on the fan, Thanks!

WanMan, Go for it!

By conventional standards half the people in this forum are doing things that are crazy...whether its spending half the years mortgage payments on a projector, dedicating house-space to entertainment rooms, or...

in my case:

Blacking out an entire wall of sliding glass doors, hanging over a hundred square foot of black curtains on the walls, and popping wiring holes in the walls while suspending a 140 pound projector from the ceiling-----in a rental apartment. (A share of Enron is now worth more than my security deposit return at this point)

So...conventional standard people will have conventional tvs, conventional pictures and conventional home entertainment experiences.

We, on the other hand, have the surreal-----the transcendental. If that involves an air conditioner and some ductwork, so be it...just make sure to share your design.
Note to self: Start shopping for an air conditioner
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Considering a 110LC from Terry or Curt.

Reading threads on hushbox design, noise and heat.

I haven't run into any comments yet about noise cancellation technology. Haven't read the earliest threads from the search tho. This would have to be mostly enclosed in a box with mics strategically placed and a speaker or two inside the box also. Don't want to cancell the soundtrack.

Ignore if crazy or already attempted.

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Or maybe some cancellation of the soundtrack is desirable inside the hushbox.

A box in a sound environment will boogy to the soundtrack not so sweetly. That is why we shouldn't have cardboard and wooden boxes in the sound environment. Mucks with tonality and resolution.

To make an acoustically inert hushbox one would have to use well designed box walls and internal bracing. Not too likely.

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If you are intent on replacing the fans or modifying them, take a look at Gizzo's fan page (it's mostly used by the DIY PC/Overclocker community, but it applies here, too): http://gizzo.8m.com/fans/ . It will give you a list of most comparable fan models for a given size. Try to match air flow as much as possible. You will be amazed at how much variation there is.

One caveat to Gizzo's page: he uses the published fan specs. These can sometimes be wildly optimistic, so YMMV.


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