CurtPalme.com Home Theater Forum

diezzler · Joined: 23 Dec 2010 Posts: 38 Location: Potomac, MD

I recently changed all the fans on my xg to quiet it down, and for the most part, sounds alot better, other than going the route of a hushbox. I followed a forum on avs forum that was about 5 years old, and decided to post on that forum, eventhough i'm sure no one will see it. I thought i'd copy what i wrote to see if anyone on here had any thoughts on the idea.
Its basically about using a tachometer signal that is found on most computer fans and using it to signal the locked rotor alarm signal found on the stock fans in most electronic devices (i'm assuming most crt projectors too).

"I know its been years since anyone has been active on this forum post, but i've used alot from this forum to quiet down my xg. One thing thats been bugging me is the lack of saftey with the projector and fan failure. I've been thinking of ways to change the tachometer signal of the pc fans into the locked rotor alarm signal. Basically in the locked rotor alarm signal, when the fan stops, the yellow wire (alarm signal) goes high on fan failure/stopping (wire will now have voltage). On tachometers, there is either a pulse of 2 or 4 per each revolution of the fan (an oscillating signal). I think it would be really easy to measure the voltage of the oscillating signal, add a capacitor (for some "buffering") and tie it into a relay that will switch the relay to "on" tgoing o grounding (this basically will go to the yellow wire on the projector and be grounded/go low, indicating the fan works, when the osicallted signal powers the relay). If the fan fails, or rpms become too low, the voltage decreases to the capacitor and it won't be able to hold the circuits specific constaint charge, the certain voltage/oscillation from the tachometer that comes from the fan that turns the relay "on. The relay will lose power, and the off state of the relay will then occur, which will be tied to a posite value (whatever the value is of the going high in the locked rotor signal alarm). This should then send a positive voltage to the yellow wire going to the projector indicating a fan failure.
The only problem would be figuring out the voltages, and finding a relay that will work in this voltage/amperage range. And, this circuit would need be made for each fan, or have all of them tied into one (one fan fails, they all send a fan failure signal).

Any thoughts?"

-Cliff

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

Do you use your XG with a computer? If you do, you can easily run the yellow wires to the computer's mobo and use the monitoring program to see the fan speeds, and also set it to give an alarm on screen as well as audible in alot of cases in the event of fan failure, and most main boards these days have quite a few fan plugs on them.

diezzler · Joined: 23 Dec 2010 Posts: 38 Location: Potomac, MD

Yea, i thought of that, but I don't solely rely on the computer. I also thought of just using a fan controller (a few of them), but where would i put them? I just wanted to try to mod it to be "stock" like. My computer is also my web hosting server, so I barely go on it (its rack mounted). The 2nd monitor hdmi output on it has xbmc running 24/7 and is tied into a matrix which is all controlled by my automation system (goes to 4 tvs around the house). In the end, it would be a pain. Not to mention I'm sure there aren't anymore fan plugs available as the server is 2u big, with 8 drives, and 6 fans. (The computer was to powerful to only use it as my web server)

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

hmmm... Sounds like this computer is allready over worked and under paid!!! Hahaha!! Wink

Although 6 fans for all that? I remember the old Athlon Barton core over clocking days with the ATi PowerColour 9800PRO in there and the 2 WD Raptors in RAID 0.... counting the video card and CPU i had 15 fans in there at one point!! Turn it on at a LAN party and everyone turned around to see what the hell just started up!! Laughing

**AnalogRocks** · Posted: Fri Jan 27, 2012 3:23 pm Post subject:

My Windows 98 box has 32 fans.....

External fan controller sounds like a good idea. The ones with the LCD readouts. Couldn't you find some skinny ones to attach to the back of the projector?

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

Were they analog fans? Laughing

Did you use analog gauges to display their speed? Or were they the common electronically comutated 80mm Sunon 6,500rpm screamers?

zaphod · Joined: 16 Jun 2006 Posts: 2002 Location: Cloverdale

what fans did you use as replacements for the stock XG fans?

MrGogo · Joined: 07 Sep 2006 Posts: 21 Location: MTL, QC

I second zaphod's request. I recently move my XG to a coffee table setup and it sounds like theres a plane in my room!?

What type of fans did you replace the stock ones with?