Ampro 3300 - Case Cooling Question - AVS Forum
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post #1 of 7 Old 02-13-2003, 03:12 PM - Thread Starter
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My Ampro 3300, which is ceiling mounted, has two fans mounted at the top, which pulls fresh air DOWN into the unit directly above the CRT yoke assemblies, where I presume the heat inside the PJ is forced out the front of the unit around the CRT's.

When the PJ is table top mounted, those same fans pull fresh air UP from the bottom.

Does anyone else think that the Ampro's ventilation scheme, using fans to push fresh air down (while heat rises) seems flawed for a projector in a ceiling mounted assembly? (FWIW, it appears to me that many projectors, especially modern LCD\\DLP's, are not optimally designed for cooling in a ceiling mounted configuration).

I am considering adding a third fan mounted on the top (bottom if table mounted) roughly above and slighty forward from the Spellman HVPS, and behind the CRT neck cards. This fan would rotate in the opposite direction, and would pull the heat UP and out. It looks like there is plenty of room in the case to do this.

I think this would help cool the inside cavity more efficiently.

Does anyone see any potential problems with this idea? Am I overlooking some important engineering concept that messing with the stock cooling architecture would harm?

I'd appreciate any thoughts or comments.

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David

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post #2 of 7 Old 02-13-2003, 03:37 PM
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The air is forced out the back, not the front.

If you make any changes, you need to make sure all of the heat sinks on the circuit boards in the back of the machine get adequate cooling. I don't recommend pulling air out from the location in front of the Spellman, but maybe pushing more in at that location would work.

Before making changes, get baseline temps. Check the temps after the changes to see if things have improved.

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post #3 of 7 Old 02-13-2003, 06:55 PM
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You have three fans as it is, the one that blows into the power supply is also used to help pressurize the chassis.
The Ampro cooling system is great for modification.
If you really want to make it cool better, seal any area that do not have heat sinks at vent openings...these would be areas around the access door circuit boards...I even sealed up much of the rear vented area, leaving areas around any board that had heat sinks open.
There is much you can do, but as Thurman says, get several temp sensors, and keep a close eye as you make changes...give your changes about 15 minute to stabilize.

DO NOT mount a fan that pulls air out of the unit...if anything you would want to blow more air into the chassis...and idea of Ampro's cooling system is to PRESSURIZE the inside of the chassis. More pressure will create more cooling air moving past all heatsinks.
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post #4 of 7 Old 02-13-2003, 08:50 PM - Thread Starter
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Thanks Thurman and KennyG!

That's very interesting. So all of the PJ's exhaust heat is dissapated out the back of the unit? IMO, that seems very inefficient.

What would you guys think about, in addition to adding a third fan on the top that would push more air into the unit, adding another fan in front of the rear openings to pull more air out the back? In other words, you would have the PS fan pushing air in, and another fan pulling air back out?

I know that the Spellman and SMPS get so hot, and generate so much heat on their own, that there's got to be a way to cool them down a bit more, thereby extending their precious life.

FWIW: My system and power supply temp typically reaches 47 degrees C. (116 degrees F)

Thanks again for your suggestions. :)

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post #5 of 7 Old 02-14-2003, 08:08 AM
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Putting a fan at the back on the side with the horizontal and vertical boards to pull air out might be worthwhile. The heatsinks on those boards generate a lot of heat.

Thurman
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post #6 of 7 Old 02-14-2003, 01:26 PM
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I wouldn't install any fan pulling air out of the unit...the rear isn't the only place that cooling air exhausts from. Take a look at both the boards mounted on your access door, see those heatsinks? If you start "pulling" air your going to cause loss of cooling air over those sinks.

Now let me confuse you...if you want to pull air, remove both the big fans. Punch a 1.5" hole directly over each neck board.
Buy a large metal paint roller tray and a 4" duct flange...flip the paint tray over and mount the 4" duct into the paint tray. duct tape this into the top of your Ampro, making sure is covers the three neck board holes and both the large fan openings.
This will give you an upside down paint tray with a 4" metal duct sticking out the top...and it gives you a vacuum manifold.
Now run some ducting in your attic, to a 70 or 80 CFM fan and you have an almost silent pj that is remotely cooled...and it runs cooler than original designs!
Later when I have time I'll find the pictures and post the link.

My suggestion is either blow all the air in...or suck all the air out...DON'T do both.
AND NEVER EVER remove the fan from the rear...your power supply will burnup in about 5 minutes...I know from experience! :(
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post #7 of 7 Old 02-15-2003, 08:15 AM - Thread Starter
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Well, I suspected that the concept of case cooling would be more complex than what it may appear.

Those are very interesting suggestions, KennyG. Could you please post the pics of your externally vented cooling system set-up?

Is the fan you're recommending something like one from a bathroom ventilation fan? What kind of fan do you recommend?

I remember seeing a company that has introduced an attic or remote mounted cooling fan assembly, and the duct work is designed to fit within a standard 2X4 wall cavity (for ventilating cabinet mounted AV equipment) and comes with a remote contact closure for turning the fan motor on and off. It was pretty expensive though...$250 dealer cost IIRC. But the concept of remotely mounting the ventilation fan was similar to yours.

I'm not sure I'm ready to dive into that yet, but I am going to start thinking about it.

Thanks,
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