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Old 9th January, 2005, 06:05 AM
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Chernobyl Chernobyl is offline
Projector Wizard
Join Date: November 2004
Location: UK
Posts: 594

Originally Posted by Cesium
what exactly is the cooling layer? is that the hemisphere that sits around the bulb? if so, mine appears to have a full spectrum of iridesense

another thing, the upper middle of my screen seems to be lighter than the rest and im almost certain its the lcd... exactly how hot can lcds get and do they show any signs of being too hot?

nanoman, i bet 7 meters would still work even though that is fairly lengthy
im using a 6 foot vga extension and i cant tell any difference
Ah, I hoped you could see. This excerpt is from a 3M 9100 brochure:
"The cool stage on the Model 9100 keeps transparency film from curling and prevents harm to LCD projection panels."
I wondered if you could see the cool stage easily.

Is the brightest part the centre of the OHP? It may be the bulb gives a little more light to the centre. Alternatively...
The lower part of your screen may be getting hot. Mine darkens as it gets hot until no light can pass. A 120mm cooling fan @ 7V blows air under and over the LCD from the side, its very effective and quiet. 5V may work fine for you.

I did some temperature measurements with a dead panel sat directly on the OHP glass. It reached 50C but the LCD wasnt operating (darker picture absorbs more heat and the LCDs own heat generation counts too). I read some tech specs a while back and (memory withholding) the max operating temp was around 55C for the panel they had.
Try allowing a little air to flow under the LCD by raising it slightly, it may be enough to stop browning. I do recommend a flow of air though for the sake of a longer life panel.
Attached Thumbnails
Home made projector!-max-temp.jpg  
2.9m DIY home made LCD PC projector !
Venice 3000+ (1.8GHz) @ 2.7GHz, 1.4V
Stock air cooler
X1800XT clocked to PE

Last edited by Chernobyl; 9th January, 2005 at 06:16 AM.
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