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I've been wondering about the best practice if I plan to take a break from watching something and plan to return later. when is it better for lamp life to avoid another start cycle vs. leaving the lamp going unwatched? Does it matter or not to bulb longevity? What is the break even point, fifteen minutes, half hour or some other interval?
 

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I've heard leave the projector on at least two hours and that is what I try to do. I have no facts or studies to back this up, only what I've heard.
 

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I have had 3 DLP projectors over the past 5 years. My current BenQ is on it's 3rd bulb just recently. I reset the timer at 2000 hours on the first 2 bulbs and took them an additional 700 hours before "thermal" issues arise and require a new bulb.


We have cycled the PJ OFF for less than 5 minutes sometimes. We have run the PJ ON for

Never saw a bulb that did not last at least 2600 hours plus. Now some may say I could have got 4000 hours out of them but 2700 hours for a 2000 hour rated bulb is o.k. by me. I have a hi-power screen so plenty of light. I dial the iris way down the first 1500 hours anyway.
 

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I don`t think anyone really knows. One would think you should leave it on for a few minutes before turning it off just to let the bulb warm up to operating temperature. My guess is that one should shut it off when not watching for any substantial period of time. Obbviously, something perhaps approaching 0.5 hours. Nothing science here, these beasts take a lot of power and power costs money. Also one says time on bulb hours. I would not leave a machine on for over a half hour or so if not watching it. There is no need to leave it on for a long period after turning it on. Just let the bulb heat up and then you can turn it off whenever.
 

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It should be noted that the projector lamp circuitry is different than turning on a light in your house. There the switch hits the bulb with full power, inrush and all. The pj lamp has circuitry that powers the bulb in a more elegant manner which doesn't "shock" the bulb when it's powered on. Personally, I leave my lamp based RPTV on for up to 15-30 minutes if I take a break but if I'm not sure how long I'll be out of the room the TV gets switched off. I will do likewise with my RS50.
 

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I've heard bulb strikes are the real culprit when it comes to lamp life so I leave mine on if I have a gap in use of 1/2 to 1 hour. Not too different from what others are saying.
 

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There were many discussions of this in some older Infocus threads with Bob Williams. IIRC (can't find the posts now) lamp testing performed by Infocus indicated that each lamp strike subjected the electrodes to approx equivalent wear of one hour of lamp usage.
 

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The bulbs have been improved a little since those days especially with regard to improving the wear caused by strikes. The unscientific concensus seems to be if you aren`t going to be watching for a half hour to one hour or more, one should turn it off. But we scientifically don`t know.
 

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Quote:
Originally Posted by Hughman /forum/post/19570828


There were many discussions of this in some older Infocus threads with Bob Williams. IIRC (can't find the posts now) lamp testing performed by Infocus indicated that each lamp strike subjected the electrodes to approx equivalent wear of one hour of lamp usage.

That's interesting and good to know.

Quote:
Originally Posted by mark haflich /forum/post/19570910


The bulbs have been improved a little since those days especially with regard to improving the wear caused by strikes. The unscientific concensus seems to be if you aren`t going to be watching for a half hour to one hour or more, one should turn it off. But we scientifically don`t know.

That's also interesting and good to know.


Quote:
Originally Posted by erkq /forum/post/19570554


I've heard bulb strikes are the real culprit when it comes to lamp life so I leave mine on if I have a gap in use of 1/2 to 1 hour. Not too different from what others are saying.

I'm adjusting my time to the consensus 1/2 to 1 hr then (not that I haven't gone even longer sometimes).
 

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Quote:
Originally Posted by mark haflich /forum/post/19570910


The bulbs have been improved a little since those days especially with regard to improving the wear caused by strikes. The unscientific concensus seems to be if you aren`t going to be watching for a half hour to one hour or more, one should turn it off. But we scientifically don`t know.

Those improvements needed to help offset additional lamp wear due to efforts to reduce PJ dB's.


I was incorrect anyway, I found a reference to Bob's post. This was posted by Noah Katz in 2003.


"IIRC from what Bob Williams said awhile back, each strike of the lamp consumes .1% of its lifetime, so the breakeven point for a 2000-hr lamp would be 2 hr.


Man now I'm depressed, have I been pissing my life away with this foolishness for 7 years now. sigh.
 

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Quote:
Originally Posted by Hughman /forum/post/19570828


There were many discussions of this in some older Infocus threads with Bob Williams. IIRC (can't find the posts now) lamp testing performed by Infocus indicated that each lamp strike subjected the electrodes to approx equivalent wear of one hour of lamp usage.

I believe he said that each start consumed .1% of life, which is 2 hr for 2000 life.
 

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Quote:
Originally Posted by noah katz /forum/post/19572344


I believe he said that each start consumed .1% of life, which is 2 hr for 2000 life.

Check out my follow-up post two above yours. That's precisely what you posted in 2003. On a positive note there's not many of us still alive from that era.
 

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All this internet jargon. Surfing, skimming, trolling. I guess skimming is something like scan a number of posts very quickly, fire off a post if you think something is amiss, and then go back and read what you fired at? I've done that a number of times. Now I know what to call it.
 

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I never power down if I'll be away for less than an hour, and normally wouldn't power down for 2, if I know I'll be using it more. It's not uncommon for me to leave mine on for 8 hours at a stretch on Sundays during football season, even if I'm back and forth doing other things.
 

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I think it also depends on how much you let the lamp cool off before restarting, especially with UHP short-arc mercury lamps apparently. I think you can look this up on Wikipedia or something, but you need to let the mercury and/or halides to crystallise before returning them to power otherwise the reaction in the lamp can shorten the lifespan.
 
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