CurtPalme.com Home Theater Forum

Wolfman · Joined: 27 Apr 2008 Posts: 27

I know that this has been a much discussed topic, but am still curious about your opinion.

We have Barco projectors in our home theater since 1996. Starting with a Barco 800 Graphics, I moved to an 808 in 1998 and then to an 808s/Iris in 2001. Then a few years ago, I got my hands on a brand new 808s Smile

While this has been a continued improvement on the pj's, I remember that the older 808's were significantly quieter. While I have read about fan upgrades, I was told that the fans in the 808 are already very good. Greg Eisenmann told me that the fan control of the later 808's were setup simply to run at higher rpm's to keep the units cooler.
He suggested to insert a resistor into each fan power cable (forgot the value) to slow them down.

Sounded like something I didn't want to attempt at the time, but I now like to address the fan noise. Since our ceiling design is not conducive to a hushbox and the older 808's were better sound-wise, I wonder what the best approach is.

Try the resistors? If so, what value? Or where is the fan control? Is there an option to move to an earlier board or chip without any negative impact?

Hope that this isn't a duplicate thread, but my search didn't quite yield what I was looking for...

Thanks,

Wolfgang

rpruen · Posted: Sun May 25, 2008 8:04 pm Post subject:

If you want to drop the basic fan speed, then why not fit diodes in the wires to the fans? Each diode drops 0.5 to 0.6V and will slow the fans a little bit, you can tweak the fan speed by adding more diodes in the feed to each fan. Two diodes would drop 1.2V etc..... Any rectifier diode of suficient curent capacity will do (i.e 1N4002)

Make sure the diodes are installed the right way to allow power to the fans, try one to start and if nothing happens to the fan at all, then reverse it and the fan should spin.

If the fans fail to spin up on power up (because you have 2 or more diodes), then add a fairly big capacitor across the diodes (200mic 5v for example). The initial charging of the capacitor will give the fan a kick, before the voltage drop from the diodes kicks in. You may also need a resistor of a few k connected across the capacitor to discharge it for the next start.

This isn't exactly an eligant solution... But it should work.

Slowing the fans down may not be good for the projector, so at your own risk.

I'm sure others here will know more about the projector, and will say if it is a good idea or not.

Richard

jkruger · Joined: 24 Oct 2007 Posts: 2435 Location: Carlsbad, CA

I would not try to slow down the fans in a barco, they are speed controlled. I was considering quieting the fan noise on my 1209s and I was quickly told not to modify the barco, like it was sacred or some such thing. I have found some newer (ten years of technological advances might make a difference) fans that have better airflow characteristics, a different type of bearing that is absolutely noiseless and quieter fan blade design than the stock fans. The only drawback is that the fans need a higher start voltage to get them going. I am working on a modification to the fan supply circuitry to overcome this issue. I'm not going to discuss it here though, There were too many naysayers when I asked about it before. Good luck.

r.bauer · Joined: 08 Apr 2006 Posts: 280 Location: The Netherlands

808s.
I don't think the fan control has changed from the 808 to the 808s. You are probably running your projector at a higher scanrate, such as 1080p. And then the 808s can make some noise.

And because the 808s fans are temperature controlled, insering diodes or resistors only helps to slow the fans down when they are running on full speed.

Ususally I am against lowering fan-speeds, but when before and after measurements are taken and when the fan noise is reduced in another way, like using more modern fan's, you may get a good result.

1209s.
Quieting the 1209s down is a bit tricky because of the really small output vent in the rear through which a lot of heat has to pass through. What does help is removal of the internal remote, the swing-out mount and the metal box that houses it inside the projector. Just a couple of screws to undo and the airflow is improved dramatically. After this mod, I find the 1209s very quiet.

Let us know what fans you will be using, always nice to see what other people come up with.

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

Removing just the top fiberglass cover and the internal remote from a 1209s is even better... Wink

r.bauer · Joined: 08 Apr 2006 Posts: 280 Location: The Netherlands

jkruger · Joined: 24 Oct 2007 Posts: 2435 Location: Carlsbad, CA

It is 82 degrees in here today and the projector was making a lot of noise with the fans at full speed so I just pulled the plastic cover, the aluminum box and it's swing out remote. When I turned it back on after pulling that stuff it had the fans still spinning at top speed but within two minutes they had slowed to what sounds like the lowest speed. What a difference that made! Thumbs Up

Wolfman · Joined: 27 Apr 2008 Posts: 27

jkruger · Joined: 24 Oct 2007 Posts: 2435 Location: Carlsbad, CA

Looking at the way the cover is designed, they really did a bad job on it. The cover tends to reroute heated air back into the intake holes on the side of the 1209s chassis. Mine is much quieter now without it and the remote box. Removing just the remote and box should be a good improvement though, it allows air out instead of trying to push it out thru the screen and into the plastic cover to be pulled back up around the sides to the intake holes.

Ile · Posted: Mon May 26, 2008 7:59 am Post subject:

jkruger · Joined: 24 Oct 2007 Posts: 2435 Location: Carlsbad, CA

This has been a big improvement making this PJ quieter. The way it is set up, the projector is only three feet above my head and the sound of the fans on a hot day before removing the cover and control box was distracting during quiet parts of a movie. I think when I get the new fans in it the noise level will be much more tolerable. I will definitely be removing some of the wire mesh covering the outlets at the rear and the center of the projector.