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Please post experience of JVC HD750/350/550/950 bulb lifetime / lamp brightness drop - Page 14

post #391 of 738
Quote:
Originally Posted by pepar View Post

It will take me a day to post more complete data and pics of what we did, but center screen without Panamorph went from 44.3 lx to 103.4 lx post cleaning, and from 33.6 lx with lens to 75.8 lx post cleaning and lining the inside of the Panamorph with blackout felt.

The "prism-y" thingy just in front of the lamp had a thick haze over it. I have pics of that I will post.

I started this on the "Official" thread and will at least post a link there to what I post here. EVERY projector owner should at least be aware of this! The difference in the picture is NOT subtle. Sunday eve we will revisit the calibration which was done last Sunday.

Jeff

Jeff -

Sounds great.
If you post pics, "how to", and pre/post measures, you might even post as a separate thread that can be "stickied" to help people out.

Mike
post #392 of 738
I have a theory that the plastic in the FPJ1 chassis offgasses less than the JVC models. Perhaps glossy plastic offgasses less than matte plastic. At any rate, has anyone with an FPJ1 gotten these 1.5x or more increases in brightness?

I got an increase on my FPJ1, but my measurements were obviously off as they measured a decrease, which clearly (to my eyes) did not happen.
post #393 of 738
Quote:
Originally Posted by chexi1 View Post

Ok, almost idiot proof. I suspected there was bit more grime on mine that I could not see, so I used a dremel with the grinding wheel attachment. I think I lost a little sharpness...

Idiot-proof is impossible; the idiots have become too clever.
post #394 of 738
Quote:
Originally Posted by lovingdvd View Post

Glad you had fantastic results. I did too. Oddly some folks report no benefit at all. One theory is that those folks may be using the newer bulb that supposedly replaced the original bulb used in the earlier runs of these projectors.

I bought a new bulb from AVS a few months ago. Obviously I don't know how long AVS had it on their shelf before shipment but I'd anticipate a significant churn. Cleaning after a few hundred hours definitely produced a good result, even with a new generation bulb.
post #395 of 738
Shelf time won`t or shouldn`t affect a bulbs performance.
post #396 of 738
Hazy prism and flake of "debris" stuck to it (staticly?) The debris was removed and looked like part of the frame had cracked (lower left).

Second prism image is after one swipe with a lens cleaning pad.

Third image is prism completely cleaned. Night and day looking at the prism and night and day looking at the image projected.




post #397 of 738
Images of lamp, lens cleaning pad used to clean lamp (showing dirt removed) and cleaned lamp.



post #398 of 738
Lux measurements ..

Pre-cleaning with UH380 Panamorph lens in place.


Pre-cleaning w/o lens.


Post cleaning with lens in place and blackout felt lining installed.


Post cleaning w/o lens.
post #399 of 738
Blackout felt installation ...

Looking into the lens, the inside surfaces were noticeably blacked where previously they had been very well illuminated. My understanding it that one of the differences between the UH380 and the UH480 is blackout material.




post #400 of 738
Quote:
Originally Posted by mark haflich View Post

Shelf time won`t or shouldn`t affect a bulbs performance.

No but it might indicate vintage which the OP thought might matter. I don't think it does unless the new bulb I bought was really an old one. I found that cleaning the prism when using the apparently current vintage (as in "version") bulb is necessary/useful.
post #401 of 738
A few observations. The gasket on the front of the lamp assembly apparently forms a seal against the opposing metal gasket at the rear of the prism. Two screws hold the gasket surfaces firmly in place, sealing the assembly and making the airspace within rather immune to its environmental surroundings. The letters PPS are stamped on the front of my lamp housing gasket, leading me to believe the substance could be made of polyphenylene sulfide, a high temperature engineering plastic, also known as Ryton. PPS is a plastic that is used in high temperature environments, such as automotive parts under the hood, electronic parts where heat is present, etc. Something has been added to the formulation to give the part its black color. It is possible the PPS, or more likely, the black colorant material could be contributing to the recurring formation of the haze upon the prism glass coating.
post #402 of 738
Quote:
Originally Posted by Jedi View Post

A few observations. The gasket on the front of the lamp assembly apparently forms a seal against the opposing metal gasket at the rear of the prism. Two screws hold the gasket surfaces firmly in place, sealing the assembly and making the airspace within rather immune to its environmental surroundings. The letters PPS are stamped on the front of my lamp housing gasket, leading me to believe the substance could be made of polyphenylene sulfide, a high temperature engineering plastic, also known as Ryton. PPS is a plastic that is used in high temperature environments, such as automotive parts under the hood, electronic parts where heat is present, etc. Something has been added to the formulation to give the part its black color. It is possible the PPS, or more likely, the black colorant material could be contributing to the recurring formation of the haze upon the prism glass coating.

I normally think of "gasket" as being something soft and cushion-y that will conform to a mating surface and form a seal. The hardness of the lamp housing and the frame around the prism make it difficult for me to think of them as gaskets. I suppose it's possible that they are made with a degree of precision that does "seal" the space between lamp and prism ... and the screws are spring-loaded. Having said that, I like the idea of the high temp plastic being the source of the haze. Though that seems like poor design to me.

I will look at it every 100 hours or so, but hopefully it is "spent" and won't do it again. "Don't haze me, bro."

We will take some more measurements Sunday eve and then re-do the calibration (and measure some more), but a quick check with a pluge indicated an ANSI contrast of 647:1 after cleaning.

Jeff
post #403 of 738
I should have used the term "seat" against instead of "seal" in my description. FWIW there are actually specifications to quantify the outgassing tendencies of engineering plastics in high temperature applications, such as this. Abbreviations used in each of the following descriptions of the various "low-outgassing materials" are examples. These abbreviations are related to the ASTM test method E595 used to determine outgassing. The material sample is heated to 125°C for 24 hours while in a vacuum and the specimen mass is precisely measured before and after the test and the difference is expressed as percent total mass loss (TML%). A small constantly cooled plate is placed in close proximity to the specimen to collect the volatiles by condensation ... this plate is weighted before and after and used to determine the percent collected volatile condensable materials (CVCM%). PPS compounds exhibit very low outgassing characteristics, unless plasticizers have been used in the formulation. Most plasticizers are volatile and therefore have a tendency to outgass even at normal tempertures.
post #404 of 738
In the context of resilient flooring, plasticizer migration leaves the vinyl discolored and brittle. I'd surmise that plasticizers leaving the housing could cause problems, but perhaps bulb life ends before any complications arise?

Jeff
post #405 of 738
Quote:
Originally Posted by pepar View Post

...We will take some more measurements Sunday eve and then re-do the calibration (and measure some more), but a quick check with a pluge indicated an ANSI contrast of 647:1 after cleaning.

Jeff

Glad you are having great results Jeff and those are awesome pics! However we need to nip this one in the bud - there is no way your pj is putting out anything even close to 647:1 ANSI CR. The measurement is easily off by a factor of 2. I know you said this was off the top of your head, but if you get those numbers you may want to double check your measurements or measuring methodology. For sure.
post #406 of 738
Quote:
Originally Posted by pepar View Post

I normally think of "gasket" as being something soft and cushion-y that will conform to a mating surface and form a seal.

True, but there are different levels of "cushion-y" for different purposes. Copper gasket are used in engines because it is softer than surrounding materials and appropriate to the application. But you wouldn't normally think of copper as cushion-y.
post #407 of 738
ANSI CR is based on a certain test procedure. Most who attempt to measure ANSI CR do not follow the full procedure, sometimes because of limitations in their testing environment. I call these tester modified ANSI CR procedures. Measuring the way your calibrator did would not even be a poor tester modified ANSI CR procedure. The room the test takes place in often really screws up the measurement.
post #408 of 738
Quote:
Originally Posted by lovingdvd View Post

Glad you are having great results Jeff and those are awesome pics! However we need to nip this one in the bud - there is no way your pj is putting out anything even close to 647:1 ANSI CR. The measurement is easily off by a factor of 2. I know you said this was off the top of your head, but if you get those numbers you may want to double check your measurements or measuring methodology. For sure.

Now that you mention it, that does seem way too high. But I'm sure it's an honest mistake and nothing really to "nip." . The email from my calibrator was:

"The ANSI (Static) contrast I measured tonight was based on the pluge pattern and should have been done with a checkerboard pattern.* Basically it is the illuminated white area (100IRE) compared to a 0 IRE area in the same frame.* In your case it was 103.4 lux (100 IRE) / .16 lux (0 IRE) = 646.25 : 1 ANSI CR."

We are going to touch up the cal tomorrow eve and will redo the measurements before starting.

Jeff
post #409 of 738
No worries. The only reason I mentioned it is that I didn't want to see a frenzy break out, with folks thinking this cleaning procedure can double ANSI CR (in fact, ANSI CR should be about the same with or without the procedure - and same for on/off CR - its the overall brightness that this procedure improves for some and the overall black level should rise as well). Over the past three or so years since the RS series came out, I'm not aware of any unit that has measured better than 300-some:1 and that's under ideal situations. This goes for the professional reviewers as well.

If you want to measure so you can have an apples to apples comparison with a common approach used around here to measure what we typically refer to as ANSI CR, I describe the technique and approach in good detail here: http://www.avsforum.com/avs-vb/showthread.php?t=755705 (I did not invent the technique, just describe it). Note that the numbers in that thread are based on my old Sony Ruby from a few pj's ago, but the technique and approach is the same. Let us know how it comes out. And thanks again for the excellent pics of the prism and cleaning. Its amazing how long its taken for word to spread about this great brightness improvement but glad it is catching on.
post #410 of 738
Quote:
Originally Posted by mark haflich View Post

ANSI CR is based on a certain test procedure. Most who attempt to measure ANSI CR do not follow the full procedure, sometimes because of limitations in their testing environment. I call these tester modified ANSI CR procedures. Measuring the way your calibrator did would not even be a poor tester modified ANSI CR procedure. The room the test takes place in often really screws up the measurement.

Wow, tough crowd.

Jeff
post #411 of 738
Quote:
Originally Posted by lovingdvd View Post

No worries. The only reason I mentioned it is that I didn't want to see a frenzy break out, with folks thinking this cleaning procedure can double ANSI CR (in fact, ANSI CR should be about the same with or without the procedure - and same for on/off CR - its the overall brightness that this procedure improves for some and the overall black level should rise as well).

If the haze is diffusive, then light that should be going one place on the screen is going everywhere. Would that not account for lower intrascene contrast than with the haze removed?

Quote:


Over the past three or so years since the RS series came out, I'm not aware of any unit that has measured better than 300-some:1 and that's under ideal situations. This goes for the professional reviewers as well.

If you want to measure so you can have an apples to apples comparison with a common approach used around here to measure what we typically refer to as ANSI CR, I describe the technique and approach in good detail here: http://www.avsforum.com/avs-vb/showthread.php?t=755705 (I did not invent the technique, just describe it). Note that the numbers in that thread are based on my old Sony Ruby from a few pj's ago, but the technique and approach is the same. Let us know how it comes out. And thanks again for the excellent pics of the prism and cleaning. Its amazing how long its taken for word to spread about this great brightness improvement but glad it is catching on.

I'm sure we're get it right the next time! I will definitely post as much data as I can.

Jeff
post #412 of 738
Quote:
Originally Posted by pepar View Post

If the haze is diffusive, then light that should be going one place on the screen is going everywhere. Would that not account for lower intrascene contrast than with the haze removed?

It depends where in the light path this diffusion is.
post #413 of 738
Well, I'm no longer a prism virgin. I cleaned my first one this evening. The hardest part was getting my paws in the little opening to wipe it clean. But I got-r-done. I was using a brand new blue colored microfiber cloth. I mention the color because on my first swipe the cloth picked up a white "powdery" substance. Not a lot mind you, but it was there nonetheless. I don't have fancy measurement equipment. But I do have my two peepers, and though the difference wasn't night & day, there was definitely an improvement. Keep in mind my bulb is pushing close to 1500hrs.
post #414 of 738
Let me see. You found white powder in an accessible internal compartment in an object imported into the United States from a foreign country. Have I got that right?
post #415 of 738
Quote:
Originally Posted by Waboman View Post

...I don't have fancy measurement equipment...

It doesn't take anything fancy really. For instance the CA813 is sufficient for this purpose. I talk all about it in the thread I linked to above.

Having a convenient light meter like this is really a great tool for the HT enthusiast. There are a lot of other users for it other than this. Having on around just comes in handy for various testing such as measuring ANSI CR or on/off CR, determining ftL, evaluating different modes of operation such as iris position and lamp mode etc.

Certainly I would not have gone out and bought this meter just for measuring the benefit of the lamp cleaning. It has however proven very useful and handy to have around over the years for various tasks. If you have a light meter like the Spyder it can be used for similar purposes although a lot less conveniently.
post #416 of 738
I recently bought the similar Tecpel 531 light meter, to monitor lamp aging, balance iris settings for lens and non lens use and to measure in room ANSI contrast improvements. It's a handy thing to have (even though I already have an i1LT) so although I was able to use it to measure approx 17% increase after a second cleaning I had it anyway.
post #417 of 738
Quote:
Originally Posted by lovingdvd View Post

(in fact, ANSI CR should be about the same with or without the procedure - and same for on/off CR - its the overall brightness that this procedure improves for some and the overall black level should rise as well).

....if the measured intrascene contrast ratio doesn't dramatically improve after removing haze like that shown in the photos above, then there is something fundamentally wrong with the metering, room lighting, or in the procedure. The haze pictured above is the same to what I have been experiencing and removing each cleaning, and looks and behaves like a Tiffen fog (diffusion) filter.
post #418 of 738
Quote:
Originally Posted by Jedi View Post

....if the measured intrascene contrast ratio doesn't dramatically improve after removing haze like that shown in the photos above, then there is something fundamentally wrong with the metering, room lighting, or in the procedure. The haze pictured above is the same to what I have been experiencing and removing each cleaning, and looks and behaves like a Tiffen fog (diffusion) filter.

Are you saying you have measured an improvement in ANSI CR post-cleaning? If so, to what extent? Or are you speculating?
post #419 of 738
....I'm simply stating that an opaque layer of haze placed in the light path cannot act as a perfect absorber.
post #420 of 738
Quote:
Originally Posted by Jedi View Post

....I'm simply stating that an opaque layer of haze placed in the light path cannot act as a perfect absorber.

I agree with that statement. It sounded from your post that you are inferring that because of that, it means that ANSI CR must therefore increase if the haze is removed. That is the part I don't see as the case.
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