# When to change the projector bulb?



## mikefellh (Feb 10, 2019)

Let's say it's not blown.

Epson G6900WU with a 6000 lumen bulb.
It's rated at 2000hours in "normal mode" (vs. 4000 hours in "eco" mode).
I got 750hours normal, 225 eco.
I was thinking of waiting until end of May (end of our season) to do it...that would add another another 130hours (over-estimation).

Figure waiting to half-life (approximately) would be a good time.

Any reason to change it sooner?

Mike


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## ruinexplorer (Feb 10, 2019)

Only reason t change it sooner is if it isn't bright enough. That is generally why I change lamps.


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## seanandkate (Feb 10, 2019)

I agree with @ruinexplorer . If your starting to see a problematic dip in output, change the lamp. If it's still doing what you need it to do, you're still good to go. If you are estimating that by the end of your season you will have less than 1000 hrs on a lamp rated for 2000, I would think that you are probably still good (again, unless output is an issue). Of course, it never hurts to have your next projector lamp already sitting on a shelf in your venue...


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## mikefellh (Feb 12, 2019)

Problem is I don't know if it has gotten darker than when it was new, because I have nothing to compare it to. It's not like I took a reading of the projection when it was new, and could do another reading now to see if it is darker.


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## seanandkate (Feb 12, 2019)

mikefellh said:


> Problem is I don't know if it has gotten darker than when it was new, because I have nothing to compare it to. It's not like I took a reading of the projection when it was new, and could do another reading now to see if it is darker.



It will be somewhat darker. No need to measure. The _real _question is, is it now _too dark_ for your application? If it's not, don't mess with success. If you want to hedge your bets, order another lamp so if your present one fails, or does become objectionable dim, swap it out. I think I swapped out my last lamp at about 2/3 of the rated life because I needed a boost for a particular application (and truth be known, to my eye, I didn't see that dramatic an increase in output. YMMV.)


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## RonHebbard (Feb 12, 2019)

mikefellh said:


> Problem is I don't know if it has gotten darker than when it was new, because I have nothing to compare it to. * It's not like I took a reading of the projection when it was new*, and could do another reading now to see if it is darker.


 @mikefellh True; Next time you install a new lamp, dutifully clean the optical path then take and record a reading for future reference. Just a thought from a geezer for whom projectors were Carousels projecting 35 mm and super slides. 
Toodleoo! 
Ron Hebbard


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## ruinexplorer (Feb 12, 2019)

Generally speaking, the lamp will start to lose intensity at around 200 hours. Again, generally speaking, you should still have at least half of your original output at the rated end of life. Most likely you will have closer to 60% output at end of life. Obviously there are other factors at play (how many on/off cycles, contamination on the optics, etc.).


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## Jay Ashworth (Feb 12, 2019)

mikefellh said:


> Problem is I don't know if it has gotten darker than when it was new, because I have nothing to compare it to. It's not like I took a reading of the projection when it was new, and could do another reading now to see if it is darker.


Here's an excellent use for an Android luminance meter. If you're measuring the same lamp in the same fixture/projector, you don't care if the absolute number is correctly calibrated.

Pick an app, measure all the relevant things next time you change them (same conditions of lens, zoom, etc), and then you'll have a baseline.


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## mikefellh (Mar 7, 2019)

ruinexplorer said:


> Generally speaking, the lamp will start to lose intensity at around 200 hours. Again, generally speaking, you should still have at least half of your original output at the rated end of life. Most likely you will have closer to 60% output at end of life. Obviously there are other factors at play (how many on/off cycles, contamination on the optics, etc.).



You say 200hours, but what is the life expectancy of the bulb you are referring to? Is it my 2000hour bulb, or a 600hour bulb?


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## macsound (Mar 7, 2019)

I don't think it matters the total life, after 200 hours an arc source lamp will have a nice amount of haze inside the glass that reduces the output a certain amount.


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## ruinexplorer (Mar 7, 2019)

None in particular. I have observed that all of them start to drop off around that point. How much depends on many factors, which is why I said "generally".


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## StradivariusBone (Mar 8, 2019)

How catastrophic is it to allow a lamp to fail in a projector?


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## sk8rsdad (Mar 8, 2019)

It depends on how the lamp fails. If the envelop fails catastrophically it can cause physical damage to anything in the path of the shrapnel. Other failure modes might cause increased current flow in the ballast and shorten the life of the power circuitry. It's probably mostly harmless most of the time but don't have any data to back up that claim.


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## RonHebbard (Mar 8, 2019)

StradivariusBone said:


> How catastrophic is it to allow a lamp to fail in a projector*?*


Posting in agreement with, and support of, Dad's post; possibly *@ship * can post with a few tails of xenon lamps which have errupted within Strong xenon Supers and / or Gladiators taking out reflectors, irises and lenses. 
Have you ever walked along a fly floor and noticed a dent where someone inadvertently dropped a 44 pound cast iron weight from the loading floor? The first time you see a Strong xenon's housing that's suffered the joys of a xenon lamp exploding within will leave you with that same horrible feeling in your tummy.
Toodleoo! 
Ron Hebbard


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## ruinexplorer (Mar 8, 2019)

StradivariusBone said:


> How catastrophic is it to allow a lamp to fail in a projector?



Truth be told, it is not good at all. Most likely, if it fails, it is because it has been run too long. As they age, the properties of the light emitted change. On the high pressure lamps used in most smaller projectors, the shift is towards the infrared side of the spectrum, increasing heat, which can damage internal components, particularly in an LCD projector. 

If a lamp fails catastrophically, you may have more issues. The projector should be designed to contain most of the damage, and the projector should be salvageable. I have had a 3k Xenon lamp explode in a projector. The majority of the bulb was contained in the lamp housing, but extremely small glass particles (glitter size) were blown out about 20 feet. The gasses completely coated the inside of the projector which required it to be sent out for service (cleaning the optics). At least these lamps did not contain mercury. Almost, if not all, of the high pressure lamps used in smaller projectors do contain mercury. Special precautions should be taken if one of those lamps explode, as the mercury will be vaporized.


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## StradivariusBone (Mar 8, 2019)

That's kinda the gist of what I've always heard, but thankfully I have avoided first-hand experience. Most projectors made within the past decade or so seem to have some sort of deterrent built into software to prevent you from overusing lamps, and I generally follow that guideline, but I have always wondered if it were as bad as it seems. 

I once broke a CFL in my garage at home and made the mistake of reading the EPA guidelines for preventing mercury contamination. It might have been simpler to burn the house to the ground and bury the ashes in a volcano.


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## ruinexplorer (Mar 8, 2019)

I agree. I think that the high pressure lamps were more of a pain to get the projector back up and running than the Xenon lamp explosion. Reading the projector log for when it happened, at least no one was in the room when it happened.


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## ship (Mar 8, 2019)

mikefellh said:


> Let's say it's not blown.
> 
> Epson G6900WU with a 6000 lumen bulb.
> It's rated at 2000hours in "normal mode" (vs. 4000 hours in "eco" mode).
> ...



So if the rated hours are about when 1:10 lamps fail in testing, how many hours are left in your use of the projector this season? Are you going to be around +1,000 hours of use? In other words over double the time you have already had the lamp in use?

As for exploding xenon lamps... I can attest to one exploded in the 10gal. explosion disposal can I left the lid off once. Yea, glass 15' away. Boy were my guys not happy with me in doing so. Cleaned up huge chunks of glass weeks later. A projector lamp doesn't have as much pressure or amount of glass. It's reflector and housing should be sufficient to contain any such blast if xenon as per above. Probably expensive to repair, but other than in being in say +1:100 range of lamps failing - and at this point not exploding, I would be mad if you removed the lamps due to hours other than rated.

But as others have related above, if there is dimished output, it's a valid reason for replacement. Pull the lamp, look at it's globe capsule. See a small cloud or some frosting.. output is dimished but probably not bad enough to replace. More than that, that cloud becomes like the coating on a flourescent lamp in wash and isn't really arc gap center pure for say video projection. Than it's more a debate about how clear you accept. By the way, clean lenses and not mentioned filters and fans while there in maintaing the fixture. Look for fog goo buildup to clean. Tough to clean a reflector lamp reflector, but a good Kem Wipe (hospital grade cleaning wipe) should be sufficient to help remove fog go or pyro dust off a reflector. Goo and dust collects heat and prevents light reflection. Many details.

750 hours and wondering if rated for 2,000 hours if you should replace the lamps.... give a good cleaning.


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## mikefellh (Mar 23, 2019)

I just started reading the procedure for my projector to see if it's easy to do, and I found the following warning:

"If you continue to use the lamp after the replacement period has passed, the possibility that the lamp may explode increases. When the lamp replacement message appears, replace the lamp with a new one as soon as possible, even if it is still working"


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## ruinexplorer (Mar 23, 2019)

Always good advice.


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## Jay Ashworth (Mar 25, 2019)

In fact, we're going to change out ours this week.

The current incident reading on the uncalibrated app on my phone was 10-11 lux at the back wall of the stage, with full white on the screen, and everything else off.

Without zooming, I'll be able to compare that to what we get with the replacement, even though it's uncalibrated.


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