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Discussion Starter · #1 ·
Hi everyone


If you visit the digital PJs forum, then you've probably seen some of the questions I've asked there. I'm currently shopping for my first projector, and although I'm currently leaning towards a D-ILA PJ/Panamorph lens combo, I'd like to explore all options before parting with the money.


Having seen the quality a good CRT can achieve, there's only one thing keeping me on the digital camp: Maintenance. Having read so much about all the tweaking CRT owners do to their hardware, I'd like to know how much of it is essential, and how much is optional tweaking done in the quest for the perfect picture.


- I've read a lot about convergence adjustment. How often does this have to be done, and how elaborate is the process? Would I have to remove the projector from its mount in order to do it? (that would be one hell of a back-killing drawback ;))


- How do CRTs handle 16x9-enhanced signals? Would I need a third-party lens such as the ones needed for 4:3 digital PJs?


- Also, how long can I expect the CRT tubes to last before they need to be replaced? And, how easy/hard is it to have them replaced? (Assuming I had a more-or-less popular model)


I know that digital technology continues to improve, and sooner rather than later they'll provide a comparable experience to CRTs. Would it be a sound choice for someone with no front projection experience to acquire a good used CRT unit until digital technology improves further? If I found a suitable one, would I be able to hold on to it for more than a couple of years?


I know you've probably gotten all of these questions before, but if you could answer them once again, I'd be very grateful :)


-- Jorus (who never thought choosing a projector could be harder than buying a car)
 

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If you set the projector up right the amount of ongoing maintenance is very limited. You can touch up the convergence every couple of months if you want, but that takes about 15 minutes max. Every display device including CRTs needs calibration for gray scale etc. but that doesn't need to be tweaked ordinarily once it's done.
 

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Hi Jorus,


Full convergence adjustment - that is, the kind talked about most of the time in this forum - should only be needed once for each input signal type. As Jim noted, though, mechanical setup is critical for this.


You must perform convergence adjustment while the PJ is mounted in its final position. Incidentally CRTs are designed in such a way that most aspects of them can be serviced without dismounting them from their installation position.


16:9 enhanced signals - well, "it depends". Mostly your scaler should deal with it for you, although my PJ (an NEC 9PG) seems to take the DC bias applied with 16:9 signals into account when considering which input signal memory to use. Perhaps you should do a search on this topic; there's been lots said and there are several different approaches.


CRT replacement is a pain, and it's expensive, but most PJs rate their CRTs for 10,000 hours life or more. How much life you actually get depends on how hard your drive your CRTs - if you set up your PJ for 'oncoming headlight' brightness then they won't last as long as a more sympathetic setup. CRTs certainly aren't like digital PJs in which a lamp needs replacement every thousand hours.


As for whether you should go CRT, it's really your choice. Reading this forum it should be pretty clear to you that CRTs give a superior (if less-bright) image than digital PJs, for the price of increased bulk and setup fiddliness and less general convenience. The question is, into which side of that trade-off do you fall?


- David Eddy
 

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I'll go with what already has been said too in the replies.


You don't need a third party lens for 16:9 images. What is displayed is what is delivered to the CRT in the signal or else you do it through the set up process, i.e. streching a 4:3 image to fill a 16:9 area or vice versa.
 

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Some other thoughts:


How often you converge is a combination of the quality of the install, the age and quality of the projector, how much temperature fluctuates, and how anal you are. That being said, considering you're looking at a DILA/lens combo, for that sort of money (or even half of that), a used CRT projector will be a very good [high-end] unit that should be incredibly stable. If you're fussy, you'll probably end up doing a 5 minute touch-up every few months (no need to bring the projector down - that would be nearly impossible!).


How fussy you are is the big issue. A G20 DILA I saw a few months ago had more convergence problems then my projector under normal use. There were obvious (though slight) red/green borders at the right edge of the screen on white objects. I noticed it immediately. As far as I know, nothing can be done about this!


The other reason you probably see so many people talk about tweaking their CRT units is the fact that, well, they can! The units are infinitely flexible due to their nature, so there's always room for improvement.

IMHO, you need to take what you read in this forum with a grain of salt sometimes. A lot of these tweaks are people looking to pull out the last percentage or two of performance out of their units. Nothing wron with this - they do this because they can. But many of these tweaks are far from necessary.

"I know that digital technology continues to improve, and sooner rather than later they'll provide a comparable experience to CRTs. Would it be a sound choice for someone with no front projection experience to acquire a good used CRT unit until digital technology improves further? If I found a suitable one, would I be able to hold on to it for more than a couple of years?"


Very true. We're not quite there yet with digital projection, but we're getting close. If you purchased a good 8" CRT unit in the $3-6K range (Sony G70, Electrohome Marquee series, NEC XG series, Barco 1208 or 808) with unblemished tubes you'll be good for 8000-10000 hours. This could easily last you 10 years even if you watch ten 2-hour movies a week!


You also asked about replacing tubes on projectors... and yes (as someone mentioned), this is work best left to technicians because it's fairly complicated. But under normal circumstances, a CRT projector with unblemished (no burn or wear) tubes will last you long enough that by the times the tubes DO need replacing, you'll probably be looking for something more up to date. IMHO, the only time that tube replacement is a an issue for most of us is if you buy a high-hour used CRT projector that needs tubes replaced immediately or in the near future. (These sorts of projectors can be had very cheaply as the tube replacement process is not an easy [or cheap] one. When buying used, tube condition is EVERYTHING!).


Food for thought...


Kal
 

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Discussion Starter · #7 ·
I feel the pull of the Dark Side... ;)


A few more questions, guys:


- How available are CRT tubes? Can I simply buy a projector and not worry about needing to locate replacement tubes later on, or should I buy a spare set now to keep stored till they're needed?


- If I decide to go for a CRT, will I have to rely on ebay to find a used unit? Or are there any other retailers/etailers that might help me?
 

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Jorus,


I wouldn't bother looking at getting an extra set of tubes up front. Assuming the current tubes you get are ok, who knows if you'll still want to run the same projector 10 years from now?


There's also company called VDC that's able to rebuild certain tubes...


There are many reputable sellers on this forum that do this for a living. There was a resent thread that listed a pile of names. See this thread starters:

Whom to purchase a used CRT from?


Kal
 
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