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Discussion Starter · #1 ·
Hi folks,

I'm new here, first post. I have lurked a bit and learned a lot but I need some help. I've been running a Sharp LCD (DW100U) projector for almost five years now. Although it was a pretty decent machine at the time I know there are bettter/cheaper things available now. That said it still serves it's purpose fine (DVDs only). Here's my problem. I just lost the second lamp in this thing. We reall don't use it a lot so in five years the first lamp ran for about 450 hours before the machine went into thermal shutdown. This shuts off power to everything including the cooling fan and the lamp broke. Tech said I hadn't cleaned the air filter often enough. Since then I've been religous about cleaning and second lamp just failed at 650 hours. These units are spec'd at 2000 hours and cost $400 a pop. One more important fact, I live at 7400 feet. Unit is mounted with perfect ventilation but is upside down (air flowing against convection).


Here's the question. Would you:


a)Just keep replacing lamps every two years.

b)Replace lamp but rig an external fan for better cooling to extend life.

c)Replace it with one of the cheaper units now available.


I know a new unit would have better contrast/black level but this unit does 1024x768 so I would loose out on resolution, although only watching DVDs this may not be a big issue. WOuld a new unit suffer the same cooling problems from the altitude?


Thanks for your advice,

Steve
 

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Steve,


Most of the newer units run their fans at a higher speed when ceiling mounted. Also, they recommend running the fan at the highest speed at higher altitudes, like yours. The fact that your lamps have failed much earlier than expected (you can get a bad lamp, BTW) means that they are running too hot (indicating a restricted air flow - the reason for the Tech's remarks). The other thing is that you probably should be running at the lowest lamp power available (if you have a choice).


I'm not sure where the fan is located (intake or exhaust) on the DW100U, but you could put another fan on the opposite vent (may or may not help). With your low usage, I would recommend cleaning the filter before every use (and certainly every week or so, if in use). You shouldn't be running the PJ if your room temperature is higher than about 75 degrees (F) at the PJ location -- If it's hotter than that, the lamp life will be shortened too.


Also, do you shut all power off to the PJ? You should be turning off the PJ with the remote only, the fan will continue running (to cool the very hot fan housing). This puts the PJ in the "Standby" mode, and it should be left there (for at least 20 minutes), unless your expecting a thunderstorm, or won't be using the PJ for a week or two (like when you're going on vacation). By the way, you should disconnect the power plug too, if you expect thunderstorms or leaving on vacation.


It might (a long shot) help to turn the AC power switch on (putting the PJ in Standby mode) and leaving it there for 10 minutes or so, before turning the PJ on with the remote. This will get the electronics warmed up a little before "lighting" the lamp. Turn-on power surges can also shorten the lamp life. Also, once the PJ is on, don't turn it off until your through viewing for the day. Turning the PJ on and off several times in one evening (or day, or viewing session) will really kill the lamp. You can't treat it like an ordinary TV set (even they will die an early death from being turned on and off repeatedly, it's just that their lifetime is much longer than PJ lamps).


If you do decide to get a newer PJ, you should be only considering a 1280 x 720 one, as a minimum (higher resolution than what you have and a 16:9 HD format). This means that you'll be spending more than $1500 vs. $400 for another lamp. It's a matter of economics, as well as performance.


Remember that the CEDIA show is coming up in early Sept. There will be new PJs announced and released, probably in Nov. or Dec. (or early next year). This means that the current PJs will be dropping in price, making them more attractive financially (at slightly lower performance than the new ones).


I hope this helps in your decision making process :D.
 

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I have an Infocus 4805 at the same altitude (7500') ceiling mounted and no problems to date. I only have 200 hours but am unaware of lamp problems at altitude. I run on low fan speed and if the noise wasn't so load on high fan I would use it to get better cooling at this altitude.


A new 4805 is just a little more than 2 of your bulbs and throws a great picture.


An alternative would be to get a PJ that is quiet on high fan for better cooling. The Optoma H57 is quiet but costs twice that of the 4805 but the H57 includes a spare bulb worth $400.


I am sure some members could make a suggestion.
 

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Discussion Starter · #4 ·
Thanks for the input. The unit only has a single speed fan, it lives downstairs in a dedicated room that never gets above 70. I control power only from the remote so it does run the fan for a while after shutdown. My wife and son are the main users so I know it sometimes gets cycled three of four times on some days. The first failure was certainly dirty filter related, but not the last one.


I was looking at the 4805 as a replacement. The refurb units (any problems there?) are less than two bulbs. I know resolution will be worse, but contrast and black levels should improve greatly. I can't really wait for long as my wife is pretty much addicted to this setup. At sub $1000 I can dump it in a few years for the next round of better/cheaper.
 

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Since you are watching DVDs only, the 4805 would be a good replacement IMO. I have yet to see any complaints about the refurb units and I believe that Infocus has a rule that the maximum bulb usage on refurbs is 200 hours (if it has more than that, they install a new bulb before sending it out). The only issue that you might have with the 4805 would be fan noise. If you can check one out before you buy a refurb, I'd do so. Good luck!
 

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Definitely go look at the 4805 first (Magnolia Audio Video stores -- also Magnolia HT in some BB stores).


Coming from a Sharp LCD, you may have problems with the SDE and motion artifacts of the 4805 -- I did. You will also have to sit further back from your screen than with your DW100U.
 
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