[ladieu]

I now have 2 120MM fans on my 15" PJ and it is still way too hot. I took the lid off the thing and let it run (with the lid completely off)

and the temperature between the rear fresnel and the heat sheild still rose to about 100 degrees (at that point i turned it off)

Very frustrated! I don't know where to go from here... please someone help!


I just thought I should add that the fans are most definately blowing air out of the box (not in) in case someone thought this was the problem


Here is the link to the fans i am using if you want to check specs.

http://www.overcool....9&item_id=34799

GRRR... making me angry

This post has been edited by ladieu: 03 April 2006 - 09:38 PM

[bevo77]

The key is to have a continuous "wall of air" washing over the LCD. The best way is to "pull" the air from the back of the PJ weaving it across the face of each panel--the LCD, the rear fresnel, the heat shield (Lexan or tempered glass) and then back across the lamp carrying all that heat out the back. Seals should be very tight. Clearance around panels should be 1/2" minimum with the first slot all the way across the LCD. If you're using an air filter, make sure it is not too thick.

Running the PJ with the top off should not be done as there is no seal for the air flow and IR energy accumulates. Follow the guide if your build is the standard box.

[ladieu]

bevo77, on Apr 1 2006, 10:38 PM, said:

Running the PJ with the top off should not be done as there is no seal for the air flow and IR energy accumulates. Follow the guide if your build is the standard box.

My box is a haas. So your thinking this may have to do with not having a tight seal?

[cornelius]

Are you using a piece of heat reducing IR glass in your pj? Or are you running the lamp open against your rear fresnal? I was using 2 fans on my 15" and found that it was too much so I removed one and still had no heat issues. Where are your fans placed? Both at the rear? I found that having one at the rear blowing out and a smaller fan on the top just behind the lcd blowing created better airflow.

This post has been edited by cornelius: 02 April 2006 - 03:43 AM

[ladieu]

cornelius, on Apr 1 2006, 10:41 PM, said:

Are you using a piece of heat reducing IR glass in your pj? Or are you running the lamp open against your rear fresnal? I was using 2 fans on my 15" and found that it was too much so I removed one and still had no heat issues. Where are your fans placed? Both at the rear? I found that having one at the rear blowing out and a smaller fan on the top just behind the lcd blowing created better airflow.

I have a piece of lexan in there with the UV filtering side facing the lamp. WIth the lid on it also raises to 100 degrees. If you check my PLOG you will see I built this with another fella. He was having the same problem initially, but all he did was slide back the lid slightly and his temperature evened out at around 95 degrees.
I tried that and it didn't work, and i have the same projector, built the same way with the same thermometer.... grrr. I currently don't have filter cloth over the holes... I don't know what to do.

This post has been edited by ladieu: 02 April 2006 - 03:51 AM

[ladieu]

Yes both my fans are at the rear. I was considering putting an 80MM fan at the top of my LCD which would suck air in and the 2 in the back would push it out... Stupid idea?

[Cold Steel]

See Haas's post HERE and look for post #11 (right hand corner of each post is a number).
make sure your air is flowing correctly.

If it is then make sure all holes are plugged, slots sealed so that the fans will pull the air through your air slot and go between your lcd and fresnel and up and over (or underneath,depends on where your air is on the top or bottom, see diagram in post 11.) the lexan to your fans.

[cornelius]

Correct me if i'm wrong, but lexan is only a UV filter. I am using a piece of the uv filter as well as a piece of IR glass. ne fan on top and two in the back is prbably a bit much. I've got a cpu fan on top pushing the cold air in, and an 80mm fan blowing hot air out of the back.

[ladieu]

cornelius, on Apr 2 2006, 09:59 AM, said:

Correct me if i'm wrong, but lexan is only a UV filter. I am using a piece of the uv filter as well as a piece of IR glass. ne fan on top and two in the back is prbably a bit much. I've got a cpu fan on top pushing the cold air in, and an 80mm fan blowing hot air out of the back.

I really don't know. I see most people here in the PLOGs use lexan as a heat shield...

[cornelius]

I don't think it would have anything to do with the top being off or air leaks, since these would only bring in air from the room and blow it out your fans in the back. I had a piece of the UV glass from diypc and tried taking out the heat IR glass, when I did this the UV glass shattered from the heat. The temp in my pj runs around 80 degrees with the IR glass in place, and way too hot without it.

This post has been edited by cornelius: 02 April 2006 - 04:11 PM

[jdjr]

I don't know if this helps but I had a heat problem in mine and I was reading the plogs a bit and came across someone (I forget who) that made a "light box" out of aluminum and air vents. They put a 120mm fan at the back of the box and vented this out the back. I tried this because I wanted to play with metal, it was pretty easy to make and it seems to work well with me.

I've got a pseudo haas box and when I first made it my holes on the bottom were too small. I noticed that when I had everything closed up with the fans on, I'd crack the top a bit and I could hear the fans change speed a bit, which led me to believe my holes were too small. I later opened up the holes into 3/4" slits and it helped a bit too.



JDJr

[bevo77]

ladieu, on Apr 1 2006, 09:40 PM, said:

My box is a haas. So your thinking this may have to do with not having a tight seal?

Air seal is vital. Also, make the opening between the LCD and rear fresnel as big as possible. This is your supply of cooling air. I would not introduce fans in the "intake" forcing air in. If the seal is good and there's adequate room for air flow, then the rear fans should do fine.

If you're not using tempered glass as a heat shield, you may want to consider it. Better to lose some light transmission than your LCD. Junk flatbed scanners are a good, cheap source for tempered glass.

[ladieu]

Hey thanks everyone for the input.

I went in and sealed everything up really good. I also took the advice and made the slot at the top the biggest possible size. Temperature stabalized at 100 degrees, which accorrding to the guide is within the acceptable range. This is between the lexan and the rear fresnel. Between the rear fresnel and the LCD it is more like 97

I think I will take the advice given here and get some of that tempered glass. For whatever reason I thought the lexan was all you needed... For now its working though and I can't tell you what a relief it was to finally watch a movie on this thing that I started so long ago.

Now I get to do the fun part.... Results pictures!