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From what I can ascertain, I’ve had green dust blobs since I purchased my VT540 new in March 2001. There’s a really nasty one at screen-center right that’s really distracting to me (since I know where to look, I guess) that’s about two and-a-half pixels at its widest point and one less noticeable one at dead screen center. No one else seems to notice it, though. If I picture mute I can see a handful of other minor ones and a dark blue pixel at screen center left that I really never notice from my seating position. I think it came that way from the factory and hasn’t gotten any better in the 300 hours (!) I’ve put on it since. I can look in the light path when it’s on picture mute and see a mirrored reflection of a LOT of dust. I’ve vacuumed the filters and took the filters out and vacuumed the unit and they’re still there. It looks like here’s my choices: try a DIY cleaning job by taking the cover(s) off somehow to get to the mirror/ panels; take it to a local warranty service center for cleaning; or try my luck with an InstaCare unit to replace it.


I called NEC and the guy gave me the phone number of a (relatively) local service center about an hour away from where I live. The guy didn’t seem very knowledgeable or helpful, but it could have been a fluke. I had to bring up the InstaCare part, and he said he wouldn’t recommend it because they’d have to temporarily charge my credit card for the privilege (sounds fair to me), but I’d also wind up with a refurbished unit that might have more hours on it than my “new†one. I’ve read some stories here about inferior 540K InstaCare models showing up… maybe the dust goes away, but the PQ’s worse. Mine is a VT540 (not K) model, manuf. in China. From what I read, I understand there’s some 540 and 540K models made in Japan, and some 540 and 540K models made in China. There may (or may not) be a consensus that the ideal is a straight-540 manuf. in Japan.


Sooo… should I try my luck with a refurb. in hopes of getting a straight-540 Japan model? I will obviously A-B the two and see if the replacement is worse, but if so, what’s my recourse… send the replacement back and keep trying?


Since I’m pretty much happy with my picture quality (though I really have nothing to compare it to), should I send it in to be cleaned (maybe at my expense, maybe at theirs?), or try my hand at cleaning it? Has anyone out there successfully removed dust blobs from their VT540 (or similar) PJs?


Thanks in advance!

Brian
 

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Whatever else you decide to do, it would probably be a good idea to build a hushbox/dustbox with a HEPA filter to avoid the dust problem happening again. I plan to do so when I make some HT changes in a couple of weeks.

Gary
 

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I was one of the ones posting about the 540K versus the 540 in earlier threads. Last week, I just sent back the last two projectors - I kept my made-in-Japan 540 with 70 hours on it! No matter what i did, I couldn't get as rich a picture out of any of the 540K models. One (out of 4) came moderately close in overall contrast and "pop" IF you turned up the contrast settings pretty steep. I was willing to live with that to get the new projector with the quick access aspect ratio - until I did some grey scale tests. I had both on for the MTV awards over NTSC Dishnetwork. Apparantly, "charcoal" is realy in for men's jackets and suits this year. I had the projectors set up in an A/B configuration (push one button and switch). Throughout the show, every time a "charcoal" colored suit came on, it looked washed out grey on the K series, and true charcoal on the 540 standard. On my fairly accurate direct view monitor, the suits were indeed charcoal.

If I tweaked the K model to get charcoal suits, the picture was too dark and dim. Strangely, adjusting the contrast (in either the "picture" control or in the white balance control did absolutely nothing to the suits. You could go from absolutely washed out to WAY over the top contrast, and the suits would stay the same.


A test with Avia revealed the same - you could get a fairly comparitive picture between the two, UNTIL you were testing grey or shadow material. THen, the 540K would basically "round off" all of the middle scale greys. It was subtle, but there. In the end, I couldn't justify picture quality sacrifice (no matter how small) for the sake of a brand new projector and some extra convenience. After all, isn't the best picture we can afford what we are all after? My recommendation would be to keep your 540, or order the Instacare one and do a test yourself. Then, keep the one with the best picture. NEC doesn't really care which one you send back. By the way, I tried the vaccum fix for a VERY light green blob in center. I used the little attachment that is somewhat oval with bristleas around it. Its about the size of the intake/exhaust vents, all of which I vaccumed. The blob is gone! THis doesn't make a lot of sense to me, because I have disected an older 540, and the air path doesnt really enter the LCD area or behind the lens. I'm not complaining though - a free fix is a free fix - pristine, sharp, high contrast picture (400:1), bright (almost 1100 ansi as measured by a meter in my home), BEAUTIFUL colors (and currently, I only run s-video in. Can't WAIT to try HTPC), great flexibility, and an incredible warranty and support, all for less than $2500 (B stock). Power to the budget-minded home theater enthusiast!
 

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I have the 540K model (China) and I have a good pluge screen, a good SMTPE bar screen, a good grey scale, a good "color of grey" adjustment.

I used the Video Essentials DVD, and you must pay attention to contrast, as this does affect the grey scale.

I set the brightness first, then instead of using that "pin-line test to set the contrast, use the grey-scale test to adjust contrast... You'll be able to get the grey scale and white adjusted using that one screen.

After adjusting for color, tint, color of white, go back and minimally re-tweak the contrast.

Only make changes to Contrast-Red, Contrast-Green, Contrast-Blue to correct for the "color or grey". Don't mess with Brightness-Red,G,B at all.

Use the standard brightness, contrast, color, tint to do normal tweaking, as the standard adjustments interact with the advanced adjustments.


Gamma correction? change that and you get to start all over again, so pick gamma first. I ended up leaving it a normal in order to get well-behaved greens, and excellent contrast. I did notice the total contrast reduce with any gamma setting other than "normal".

I also use the Lamp-Eco mode. While watching a movie, you barely notice the difference while changing between the two lamp modes, so might as well save 1000 hours.
 
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