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listenlounge
Joined: 29 Apr 2007
Posts: 48
Location: NSW, Australia
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| Posted: Fri Aug 07, 2015 2:45 am Post subject: Fan and Airflow Direction on Marquee belly fans - which way? |
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Gents and Ladies
I have recently discovered that my Marquee was modded somewhat before I purchased it. My assumption is that the previous owner wanted to make it quieter.
They cut the 3 belly fans supply leads and soldered in series a 10W wire wound 150 ohm resistor on the positive lead. It reduces the voltage across the fan from 24 to about 15 volts - with a subsequent increase in production of heat from the resistors, a slower fan speed, lower air volume - but hey! It's quieter!.
Anyway - I have reinstalled said fans and wondered if they had also tampered with the fans themselves during the brain-fart and perhaps reversed them, SO
Can someone confirm for me please whether the airflow in a Marquee chassis is FROM the base UPWARD and over the tubes or SUCKED FROM THE TUBES and expelled out the belly.
If it matters - My unit is ceiling mounted.
Cheers
Ben
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barclay66
Joined: 27 Jun 2011
Posts: 1304
Location: Germany
TV/Projector: Marquee 9500 Ultra
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| Posted: Fri Aug 07, 2015 6:56 am Post subject: |
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Hi,
The intake is at the PJ's bottom chassis plate (which is on top if the Marquee is mounted at the ceiling).
Parts of the air are blown into the two board cages (HDM and FGM) and the rest goes into the tube housings.
Air flow can be reversed (useful for a ceiling mount situation only) but You will need two additional fans then. One for each board cage (located on their top) as otherwise the HDM and FGM would get too hot. Sucking air is nowhere near efficient as pushing it...
Regards,
barclay66
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listenlounge
Joined: 29 Apr 2007
Posts: 48
Location: NSW, Australia
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| Posted: Fri Aug 07, 2015 9:31 am Post subject: |
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Sweet!😀
Thanks
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Fri Aug 07, 2015 1:44 pm Post subject: |
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I personally would put those fans back to stock. The HDM will run hotter and the lifespan will be shortened. Most of the fan noise comes from the LVPS.
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listenlounge
Joined: 29 Apr 2007
Posts: 48
Location: NSW, Australia
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| Posted: Fri Aug 07, 2015 10:02 pm Post subject: |
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Cheers Curt. I was thinking about putting some maglevs in it. The current fans are after market Papst fans and to top off the homebaked mod, 2 of the fans had seized. Glad I dismantled it for a clean!
The maglevs are quiet, and between the 3 pump out about 350 cfm of air. What do you think?
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Fri Aug 07, 2015 10:12 pm Post subject: |
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I don't do mods at all,as I lack the time to be able to properly research them. Do a search here and on the avsforum regarding fans and CFM, etc, there's lots of posts in both places, as fan mods were all the rage 10-12 years ago. 
I run two Barco 909s, and just turn up the volume to mask the fan noise. 
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listenlounge
Joined: 29 Apr 2007
Posts: 48
Location: NSW, Australia
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| Posted: Sat Aug 08, 2015 12:07 pm Post subject: |
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Gotta admit, your logic is sound. You can never have too much SPL.
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HK-Steve
Joined: 15 Jul 2006
Posts: 849
Location: Switzerland
TV/Projector: Marquee 9500, Epson 8100
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cmjohnson
Joined: 03 Apr 2006
Posts: 5180
Location: Buried under G90s
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| Posted: Mon Aug 31, 2015 5:00 am Post subject: |
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From an engineering standpoint, natural convective airflow has warm air rising, so it is most efficient to encourage warm air to rise rather than to try to force warm air to drop. Cool air should be drawn inwards, warm air exhausted upwards and outwards. So airflow should be upwards and the fans should be oriented so that they direct cool air upwards to warm circuits and tubes, and additional fans extract heat from the top to the outside world.
The Marquee was not designed with fan reversal in mind but that doesn't mean YOU can't do it.
At the moment I can't recall which way the stock fan arrangement directs airflow. My GUESS is, based on the assumption that
most Marquees would be installed in a ceiling mount application, that the factory airflow pattern should be correct for a ceiling
mounted projector.
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tschaeikaei
Joined: 08 Apr 2013
Posts: 490
Location: Germany/Saarland
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| Posted: Thu Oct 01, 2015 8:20 pm Post subject: |
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You are correct, the original NMB fans suck the air from the bottom and blow it through the HDM, FGM and all three tubes.
The air leaves through the top cover.
You want it quieter than original? I have taken lots of time and effort in devellopping a cooling system that does get the projector cooler than stock
at a fraction of noise. Have to upload the videos when it is finished. And it is finished about 95%.
Regards, Julian
Edited the first sentence, it was complete bull****.
_________________
Marquee 9500U edgeblend P43 | NEC 9PG
Last edited by tschaeikaei on Fri Oct 02, 2015 9:25 am; edited 1 time in total
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koldby
Joined: 07 Feb 2007
Posts: 126
Location: Denmark
TV/Projector: GJAKY modded VDC marquee 9500lc ultra
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| Posted: Thu Oct 01, 2015 10:05 pm Post subject: |
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Pls let us know!!!
A cooler running Marquee with less noise?
Cannot wait 
_________________
What is home theater without good sound?
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tschaeikaei
Joined: 08 Apr 2013
Posts: 490
Location: Germany/Saarland
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| Posted: Fri Oct 02, 2015 9:29 am Post subject: |
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The system we build is a complete and drastic change of the original cooling System. I will write about it in another thread.
Regards, Julian
_________________
Marquee 9500U edgeblend P43 | NEC 9PG
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