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Discussion Starter · #1 ·
I'm looking at the mounting instructions and they call for 12 degrees to the screen + or - 3%. If that is reduced to 8-10 degrees, will it be a problem? I'd like to adapt my existing ceiling mount to the 9PG plus. It is perfectly centered on the screen and is at a perfect distance to the screen. It is just 5.5 inches lower than called for. I could lower the screen, but I like it where it is and at that height, the little ones can't look into the path of the light. Thanks,


Chip S.

PS I,m new to NEC so be nice;) .
 

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A lower angle is actually easier than a greater angle. The one caveat is to verify that you have enough room on the ceiling mount to allow the projector to tilt slightly upwards if you place the screen higher.
 

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Chip -


If you're ambitious and not afraid of a little experimentation, I recommend finding small flat washers and, after removing the lenses, sliding one or two on each of the bottom lense mount screws. It's sorta like a crude (yet effective), Scheimpflug adjustment. We did something like this last year with a floor-mounted 6PG and it worked very well.....nice and sharp all the way out to the corners.


I found the thinnest flat metal washers I could find at the local Home Depot and ended up using 3 on each stud. Offhand, I think they added up to about 1/10th of an inch in thickness. But be very careful when tightening the lenses back down, especially where there are no washers as the plastic lens mount is no longer meeting the metal CRT mount perfectly flat....and overtightening could crack the plastic. Just make it a little snug, not real tight.


Seems there are plastic rings that were (or maybe still are), available from NEC that are designed to change this angle of attack. I've seen them but don't know how or where to get them. They're slightly thinner at one end, and thicker at the other, sorta like shims.


Good luck,

Chris
 

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Discussion Starter · #4 ·
I can tilt the PJ up no problem as the ceiling has a 12/3 pitch upward towards the screen. Speaking of scheimpflug, how the heck do you fine tune this adjustment on a NEC? I'm used to the 5/16 allen bolts on e-homes. A quick look inside showed none. Maybe I missed something?

I just picked this up today and it looks new inside, not a spec of dust. The lenses look perfect but the old flashlight test, well I had hoped for better. If you look real close you can see Windows ME on the green and blue and could not see anything on the red. I'll use it as is for now to make sure it's reliable. As soon as 1 or two of the other PJ's sell, I'll turn them into a new set of tubes. I had much difficulty useing Guy's focus directions with the ECP's because the phosphor grain is so fine but after seeing the coarser grain in the NEC tubes the job should be a snap. One thing that I noticed right away was how much quieter this was than the e-home's. The manual say's 45 db sound level. My ECP from the seated position put out 55 db. Well, time to start a new learning curve. Thanks,


Chip S.
 

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Chip,


NEC 9PG and 9PG Plus (PG9000 and PG9100) use plastic lens spacers to set the scheimpflug angle. The PG9200 and XG series use a much spiffier infinitely-variable system set by some levers at the lens base.


The plastic spacers only come in certain sizes, pre-set for certain screen sizes. (I have 2 sets for my 9PG, one for 80" screens and one zero-angle set euphemistically titled "60-200". The 80" set are angled, the other ones appear flat.) If you tilt the projector's base off normal with respect to the screen you'll need to adjust the lens vertical angle to compensate if you want razor-sharp edge focus - thus, Chris's use of washers.


To see the spacers, remove the lenses and there they are. If you're tilting the projector upwards, I guess you'll need the washers at the top of the lens (furthest away from the projector's base plate)? Not sure on this, I'm only a newbie. :] Perhaps someone more experienced than I can comment.


Correct adjustment is important, though, or I believe you'll never get a clear edge focus. You're talking about a 5 degree angle, which (according to my rusty trig) with a 80" wide screen is equivalent to 1.5" focal plane error at the top and bottom with a 16:9 screen and over 2.5" with a 4:3 screen.


- David Eddy
 

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Discussion Starter · #6 ·
Ok, so does this work? I mount the PJ perfectly level on my existing mount. After carefull measurment it's decided that the screen is exactly 5.5 inches higher than it should be. I mark the exact center of the screen and then another spot 5.5 inches lower. Then I use the lower spot for the initial cross hatch setup and then shim the lenses to raise to the screens center point. The more I think about this the less I like it. Even if I followed the instructions to the letter there should be some sort of threaded fine tuning adjustment. What good is a graphics grade projector when you can't dial it in exactly. Now we have only discussed edge focus with reguards to top and bottom. What about the sides? I'm starting to think the PG is a piece of S##T. How am I going to Guy Kuo the focus on this thing. It seems to me that weather I tip the PJ or just the lenses that the focal length will change. I really liked those adjustments the ECP provides. This sounds like hours and hours of hit or miss to get it t do what I want it to do.


Chip S.
 

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hi chip,


the spacer-thing is not bad, but i got an easier way.

take some piece of very thin copper about 0,8 inch x 1,6 inch in size and bend it in the middle with a 90 degree angle. now you got two 0,8 squares, one flat the other standing. drill a hole, a little more than the diameter of the lens mounting srcew in one square and make two cuts from the front to the hole. now you got a nice little thing which you can slide between the lens and the mounting block, you have just to loosen the lens mounting screw a little bit and put that little thing in between. due to the angle you can hold it in place and secure the mounting screw. try experimenting with rotating it a little bit.

if your pj is ceiling mounted all lens mounting screws facing towards the room need to be fitted, that´s for top-bottom focus, on the red put that to the two mounting screws facing to the green, the same to the blue. this is for side to side focus.

it´s a bit tricky because the screw facing to the green and towards the room needs two of them. mark the position of the top- bottom one, that will help a little.

also you may experiment with different thickness pieces of copper.

the only drawback to this method is that you are changing the position of the lens and not the position of the crt towards the lens.


hope this helps,


gerni
 

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Quote:
Originally posted by stefuel
This sounds like hours and hours of hit or miss to get it to do what I want it to do.
.....Uuuuh, isn't that sorta like an unwritten motto us CRT-ers have unavoidably gotten ourselves into?


Sorry Chip, I had to kinda laugh to myself when I read that line. As a former US President (and my neighbor), used to say, "I feel your pain."


Yeah, I too was a bit surprised to see the lack of Scheimpflug on these NEC's. I'd also worked on rebuilding several ECP's just prior to indoctrination into the world of the PG series and found myself just as frustrated as you. But after days and days of trying to balance out the edge focus with a 6PG, I took the little washers route and found edge-focus-nirvana in about an hour.


I still recommend it.


-Chris
 

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Discussion Starter · #9 ·
I had the chance to play around with this today a little. Looked around the many menu items(Lots). The PJ wasn't connected to a source and I noticed that the contrast was very low (could look directly into the lenses) even though the contrast setting was at 70%. Is there something that keeps this low without a signal input. I did not make any changes in any menus. This projector must have had one owner only. It is obvious that nothing has been touched since the original installation. I couldn't even find a screw head with a scratch on it indicating any service.


Chip S.
 

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Chip,

Quote:
Ok, so does this work? I mount the PJ perfectly level on my existing mount. After carefull measurment it's decided that the screen is exactly 5.5 inches higher than it should be. I mark the exact center of the screen and then another spot 5.5 inches lower. Then I use the lower spot for the initial cross hatch setup and then shim the lenses to raise to the screens center point.
No, it goes something like this: After centering your raster etc. tilt your projector until the cross is centered on the screen. Adjust the focus to get the center and L/R edges sharp.


Once you've done that, you need to decide if the top and bottom focus is sharp enough for your tastes. From your comments, you might want to try a Guy Kuo index card test on the bottom of the screen (if you tilted your PJ down; if you tilted the PJ up then test the top of the screen) and assess the quality of your optical focus.


If all is well, you (obviously) don't have to do any more. If it isn't, then you'll need to shim (equally) either the top or bottom pair of lens mounts on all 3 lenses, depending on which direction you've tilted your PJ. This may offset the image somewhat, so you may need to re-adjust the PJ's tilt. Iterate until (a) you're happy, (b) your shoulders are ready to fall off from holding those heavy lenses up over your head, or (c) you feel like you want to throw that HD-6 through a convenient window. :)


Quote:
The more I think about this the less I like it. Even if I followed the instructions to the letter there should be some sort of threaded fine tuning adjustment. What good is a graphics grade projector when you can't dial it in exactly.
There is a threaded fine tuning adjustment on some other projectors, as you note. It's just that the PG's don't have it. Instead you get gorgeous colour and great electronic setup flexibility. Yes, NEC eventually saw the light - the PG6200/9200 and all XG-series projectors have those spiffy little adjustment levers set so conveniently at the base of their lenses for exactly this purpose. But I think that the lack of a convenient scheimpflug adjustment is only a small tradeoff - it's not like you set up your projector every day; you set it up once and leave it for years. Right? :p


It's also a question of your pickiness. If you're satisfied with the image without all this extra work - or you do a Guy Kuo index card test and all is well - then there's no need to go through all this.

Quote:
Now we have only discussed edge focus with reguards to top and bottom. What about the sides? I'm starting to think the PG is a piece of S##T. How am I going to Guy Kuo the focus on this thing. It seems to me that weather I tip the PJ or just the lenses that the focal length will change. I really liked those adjustments the ECP provides. This sounds like hours and hours of hit or miss to get it t do what I want it to do.
There should be no need to adjust the side focus in this way; it's already set more or less correctly and vertical shimming shouldn't change the side angle of the R and B lenses. Of course you have a point: The use of set angle shims mean that the side angle is only exactly correct for the screen size indicated (80" using the default spacers) and if you want it exact for any other screen size then perhaps it may be necessary to also fiddle with the side scheimpflug.


I don't agree that the PG is a piece of S##T, Chip. It is, in my opinion, a great little projector. Sure, it's not perfect. You don't get screw-adjusted scheimpflug - yeah, that'd be nice - but you do get better colour than an ECP and EM beam focus and enough electronic beam shaping adjustments to drive you crazy. *shrug* It's all a question of tradeoff and compromise, bang for buck; if you don't like the design compromises of the PG/PG Plus then perhaps an XG or PG6200/9200, which as mentioned above do not require shimming, would be better for your needs.


In my humble opinion, of course.


- David Eddy
 

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Discussion Starter · #11 ·
Well David,

I know I'll have my work cutout for me as A, I'm not going to move the screen and B, I'm not useing a screen size listed in their manual. But I'm not scared. I will work it out. In fact, I think I just had an inverted brain fart. I think I know how to make these adjustable. I get some of my best idea's under pressure:eek: . I got it, I got it. oh oh oh oopps wrong kinda pressure;)


Chip S.
 

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I wish you the best of luck, Chip.


Hmm, you've thought of a way to make the 9PG scheimpflug easily adjustable? Wow, that sounds great - I'd be the first (okay, the second) to admit that the current system is painful if you're going for Kuo focus.


Whatcha thinkin' of?


- David Eddy
 

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Discussion Starter · #13 ·
Hi David,

Well, I've got this worked out on paper at least. I'm going to the hardware store tomorrow. I'll have this scheimbutplug adjustment thing working by tomorrow night. The lenses will have a starting point 3/16 of an inch further away from the tube, but I'll bet it will work. It WILL be "infinitely" adjustable prior to mounting the PJ to the ceiling. I WILL Kuo the focus. I spent four hours today beating this problem to death with a pensil and paper. I want my cake and eat it too. I want good color, contrast, black level and I want my god damned Guy Kuo focus.;) And ya know what. I'm gonna get it:D


Chip S.
 

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Discussion Starter · #15 ·
Hi Guy,

You know I ment that in a nice way?


Chip S.
 
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