Bulb warning ?

Discussion in 'Displays' started by Bob Sisson, Jul 31, 2006.

  1. Bob Sisson

    Bob Sisson Agent

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    The Bulb life warning indicator lit on my Sanyo projector, a while ago. I ordered a new bulb and am ready to change it, but since these things are so #$%# expensive I realy don't want to change it until I have to. (Its also a pain to get down from the ceiling)

    The question is, since no one has complained about any image deterioration, flickering, or color shift, can I keep using the bulb until it won't start? Will I hurt anything?
     
  2. Michael TLV

    Michael TLV THX Video Instructor/Calibrator

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    Greetings

    The risk is with the bulb exploding in the chamber ... which may cause damage outside of the bulb chamber ...

    Regards
     
  3. Dave Moritz

    Dave Moritz Producer
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    Hey Michael,

    Is that same risk apply to rear projection LCD HDTV's as well? Should I replace the bulb us soon as it says to?
     
  4. Michael TLV

    Michael TLV THX Video Instructor/Calibrator

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    Greetings

    While exploding bulbs can happen even when you don't expect it ... I would recommend that you don't try to squeeze out a few more hours on it.

    Once you put the new bulb in, you will almost immediately agree that it was the best way to go since you will see the overall light output go up quite a bit. The vibrancy of the image returns with the new bulb.

    Regards
     
  5. Leo Kerr

    Leo Kerr Screenwriter

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    One of the big problems, in my experience, is with Sanyo.

    With the few Sanyo projectors I've dealt with, (a) there is no written prediction of lamp life. (b) if you harass them enough over the phone, they tell you that the warning light (for this particular projector) comes on at 1500 hours. (c) they say that there is no posted lamp-life 'cause they get the lamps from a variety of manufacturers, and they range anywhere from 1000-2000 hours.

    Our take: Huh?

    My rules of projector lamp life:
    1. How long does it take for the lamp to strike? This is a general indicator of age.
    2. How long before the image is usably bright? This is also a general indicator of age.
    3. Is the color okay? This is a hedgy one; many people have a terrible "color memory."
    4. Is the image showing any flicker or other instability?
    5. Does it take more than one start attempt to light the lamp?
    6. Has any aspect of the picture changed drastically since last use?

    Allow me to ellaborate on 4-6. 4 is simple, really. If the image flickers, has a bright spot moving around, it's time to change the lamp. It might "warm up" after a few minutes, but this is definitely a sign.

    5. Some projectors will attempt to strike an arc 3 times before they report "fail." Listen; you can hear the projector try. If the projector rejects a lamp, change it. If you can hear it try, but strike the arc on the second or third try, strongly consider changing it.

    6. If the brightness or color changes drastically, and suddenly, do not pass go, do not collect $200. Shut the lamp down immediatly. Wait until it cools off, and change it.

    Background:

    Over the past several years, I've worked with a number of projectors. We're hard on them, and typically run them for 3600-4000 hours/year. Most of them are the UHP/Mercury/metal halide lamps; we've also run (and are still running) a number of xenon arc lamps.

    In my experience, I've seen 3 catastrophic lamp failures. Two were smallish UHP lamps, one in an LCD projector, one in a single-chip DLP projector. In both cases, clean out the broken glass, make sure the motors spin freely, and you're good to go. That's one of the big hazards of a shattered lamp - glass shards blocking a fan motor or the color wheel drive. The third lamp was a 1.9kW xenon arc lamp in a Roadie S12 (3-chip DLP large venue projector.) Somewhat surprisingly, the failure was confined to the lamp module, and caused no harm to the projector.

    Don't abuse 'em, don't push 'em too hard, and if there is a bang, either clean out the glass yourself, or get the manufacturer to vacuum it out for you, but they really shouldn't if you keep your eyes open.

    If you're concerned at all, feel free to cautiously check out the lamp that's in use. Not while it's on, of course. When it's cool, remove it from the projector, and inspect it.

    Mirrors often develop cracks. If a crack extends to the arc-tube, that's a potential problem. If the arc-tube is distorted, blackened, or has developed a bulge, that's also bad.

    Reminder, dispose of spent projector lamps as haz-mats. They generally contain mercury, thalium, thorium, tungsten, sodium compounds, iodines and other halogens (bromine, for example,) and often a dash of radioactive krypton gas. (Not to panic if it does break; it's hardly any at all, and will disperse quickly. Plus it's generally a very low energy alpha emitter.)

    Leo
     
  6. Allan Jayne

    Allan Jayne Cinematographer

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    The "replace lamp" indicator works off of a timer that counts hours of projector operation. Nothing more nothing less. The tradeoff between maximizing the use of a lamp versus minimizing the chance of explosion has already been taken into account by the manufacturer in calibrating that timer. Even under identically duplicated usage spans, no two lamps will behave alike. If you delay replacing the lamp all you are doing is second guessing the manufacturer and your guess is just as good as theirs.

    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     

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