CurtPalme.com Home Theater Forum

**kal**

Ok, but call me stupid but NMB doesn't seem to have the specs listed on their website for the two fans used in Barco 808/Cine8/Zenith1200 projector.

Front convergence tray fan: NMB model 3110NL-04W-B50
Back 3 fans: NMB model 4710NL-04W-B30

I can find the specs on their site for 3110KL and 4710KL but who knows if they're the same.

Google, this forum, and AVS searches came up blank. Anyone?

I'm going to replace my fans but just wanted to double check the CFM specs (among others) before doing so.

Kal

SYC · Joined: 16 May 2006 Posts: 269

Kal,
Because industrial fans are very mature, there won't be much approvement in CFM for the same size and rpm fans. We can assume they perform almost the same except the noise level. K and N are different series only. N series should be the predestor of K series. If they have the same speed index, we can assume they have the same performance. So for 80mm fan, index 5, it is 1.1m^3/min. For 120mm fan, index 3, it is 2.5m^3/min. I check the noise level, you should replace them:)
The followink link is its spec filter for your refernece. I don't know if you found it, so I list it:

See this URL

SYC

Tom.W · Joined: 09 Mar 2006 Posts: 6635

From what I remember the rear fans are rated at 80 CFM . Heres a link but can't remember the model # ....

http://www.nmbtech.com/cgi-bin/start.cgi/nmb/fanstart.html

Ile · Posted: Thu Jan 18, 2007 8:40 am Post subject:

I had 4710NL-series specs in my HD.

Japan Servo SCNDM12D4 are pretty good replacement, it have same CFM and bigger pressure, but have -5db less noise.
It's 38mm thick, but should fit...

**kal** · Posted: Thu Jan 18, 2007 4:49 pm Post subject:

Thanks Guys!

IIe's PDF confirms the specs I thought on one of them:

NMB model 4710NL-04W-B30: 119mm x 25mm, 2050RPM, 35dBA noise, 79.4 CFM

And using the K series as an example, and converting from m3/min to CFM I can presume:

NMB model 3110NL-04W-B50: 80mm x 25mm, 3250RPM, 34dBA noise, 38 CFM

So they're both pretty noisy (34-35dBA range). The SilenX iXtrema Pro fans that people seem to be buying to put in their CRT projectors are rated at 14dBA!

Kal

SYC · Joined: 16 May 2006 Posts: 269

Don't trust SilenX too much. It is difficult for me to buy SilenX in Taiwan, so I haven't tested it, but others are easy to buy. I have tested many brands, to summarize in short, the more CFM, the more noise. SilenX may be silent, but not so good as its spec, I think.

SYC

**kal** · Posted: Thu Jan 18, 2007 5:16 pm Post subject:

Yeah, I've heard that their noise specs aren't exactly accurate.

As long as they're quieter and reliable, that's all I care about...

Kal

Person99 · Joined: 09 Mar 2006 Posts: 4899 Location: Flower Mound, TX

**kal** · Posted: Thu Jan 18, 2007 5:26 pm Post subject:

Yep.

Walter's already done this and is going to confirm which ones he used.... right now with the hushbox in place, pretty much the only one I hear is the front one. The back ones have a low drone to them.

Looking at it some more, I may use a couple of thicker fans in the back along with the thinner one for the angle fan (since 38mm won't fit):

(2) SilenX IXP-76-18 (120mm x 38mm/90CFM/18dBa)
(1) SilenX IXP-74-14 (120mm x 25mm/72CFM/14dBa)

The original fans are all 25mm.

Not sure what to do in the front... Let me know what you used Walter. Did you do any before/after temp tests?

Kal

scoobydoo · Joined: 06 Apr 2006 Posts: 358 Location: Victoria BC

Kal
let us know what you come up with. My PJ is like Person99..out in the open and a little less DBA would be great escpecially for the people sitting under it. Just one less thing to worry about..other than the PJ falling on them.

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

Hi Kal,

The one's I ended up buying were the 90cfm, but I don't think they had the 120x25mm ones when I ordered or perhaps I might have gotten them instead.

But it's better to have alittle more cfm than you need. The temp is going to determine the speed of the fans anyway.

The one I used in the front wasn't a silentx type and now I don't remember what I used there, but it was a 120x25mm. If memory serves me correct I just used an older one I had laying around which was still quite because I slowed it down anyway. Even with it running fairly slow it's putting out more air flow than the stock fan did.

**kal** · Posted: Fri Jan 19, 2007 12:53 am Post subject:

Thanks Walter,

I'll order two 120x38mm 90CFM ones and one 120x25mm 72CFM one to replace the back 3 and then another 120x25mm 72CFM one for the front and build some sort of shroud and put it on an angle (and possibly slow it down since it'll be twice the CFM of the stock fan - I'll see how noisy it is).

I've got a temp sensor in the PJ now so I'll take some before/after readings.

Edit: They're ordered from bigfootcomputers.com. The 38mm ones are backordered abpit a weel so it'll probably be a couple of weeks before they arrive. Will post observations and temp/noise readings. (Though noise readings are somewhat hard to quantify given how different frequencies of noise are more/less objectionable than others).

Kal

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

HI Kal,

The only problem I had with putting in the extra thick fans was one of them covered it's connector on the motherboard so I had to wire the two fans to the same plug. No big deal really as they're all(the back 3) wired in parallel anyway. I don't recall which fan it was though.

The biggest difference in the noise was the stock fans had this real bad drone noise to them on top of the air movement noise.

**kal** · Posted: Fri Jan 19, 2007 1:54 am Post subject:

picree · Joined: 31 Mar 2006 Posts: 351 Location: Johnson City, TN

Doesn't the Barco chassis varies the voltage to the fans to modulate the air flow based upon the thermal load? Assuming I understand that correctly, one problem I ran into when looking for a replacement was the fact that every alternate fan I found had a much higher minimum voltage at which it could operate. Below that voltage the fan just stops...or won't start. The NMB's would actually operate down to a pretty low voltage (6V or something like that)...ie. speed.

If this is true then some of the alternate fans might actually be more problematic since they would wait until the chassis got hot enough to drive the fan voltage above it's minimum...ie. the fans would cycle more and the chassis might actually spend more time warmer.

My point-I would not neglect to check the minimum voltage rating for the fan of choice. I'm pretty sure that defines the starting speed for the fan. That's the only reason I still have the NMB's...I couldn't find another fan that went down to 6 volts...AND was quieter.

Curt

**kal** · Posted: Fri Jan 19, 2007 4:00 am Post subject:

Hi Curt - Yes - it's a good point. From what I've read and understood, these SilenX ones run fine down to 6-7VDC.

And like you said, you can't just drop in slower fan as the chassis will just try and run them harder to compensate. You need quieter fans to begin with.

Kal

wallace123456 · Joined: 14 Aug 2006 Posts: 2236 Location: Northwest VA area

I just did some work on a sony 1272 to quite the fans. Put in diodes and that helped. The biggest bang for my buck was isolating the fans from the metal housing by either using silicon noise isolators, or friction tape.

Might I suggest if you are going to pull the fans, might as well try the silicon isolators at the same time. I think you will be please.

http://www.siliconacoustics.com/fanisolators1.html

http://mitron.com.tw/joomla/index.php?option=com_content&task=view&id=57&Itemid=45

Look at the bottom of the page for the second web site. They have different sizes.

Model No. Description
RB-80 80mm fan gasket
RB-92 92mm fan gasket
RB-120 120mm fan gasket
RB-60 60mm fan gasket
RB-70 70mm fan gasket

wallace

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

All the fans in the cine8 are isolated from the frame work with rubber isolaters

**kal** · Posted: Fri Jan 19, 2007 2:22 pm Post subject:

Yep. What Walter said... these isolators are already in place.

I use'em all over the place too. My HTPC has them as well.

Kal

**kal** · Posted: Sat Jan 27, 2007 1:55 am Post subject:

Re: These SilenX (and possibly other) fans:

They have 3 wires: positive, negative, and some sort of control wire.

I'm assuming that I simply tie the control wire to the postive (+12VDC) line?

Kal