sharkeeper
Lifer
- Jan 13, 2001
- 10,886
- 2
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Projector bulbs gradually fade (dim in brightness) as they age, or get used up. Eventually, like any bulb, the filament will burn out and you'll have no picture.
Perhaps on an overhead projector.
Most DLP units use a metal halide lamp which falls under high intensity discharge. (HID)
Some facts about MH lamps:
You can damage the lamp if you move it while running, or change its position while running and/or hot from operation. I don't want to get into the technical facts of what causes this, but a lot of people neglect this fact and wonder why their lamp dies very quickly! This really applies to PJ's as they are frequently picked up and moved while hot or running. (DO NOT DO THIS!) If you need to move it and cannot shut down - cool off, by all means move it slowly without tilting or turning it over! That is very bad for the bulb. Excessive vibration is also bad when running so this is something to consider if your movie room has a matrix of 144 18" woofers connected to a pole pig, ahem amplifier.
The colour temperature of the emission will often shift as the lamp ages. Some more than others. Better sets can adjust for this and some cannot adjust well at all and the whites just look plain funky. The shift is always warmer. (at least on Earth it is!)
The lamps do drop off in output as they age but the transition is graceful providing you don't abuse the lamp. Lamps do suddenly fail and that's the nature of the beast. One thing is certain: if you abuse it , the LAMP WILL FAIL and SOON.
Cheers!