CurtPalme.com Home Theater Forum

[JorisS]

Hi all!

Having owned my XG110LC for about 2 years now, this evening I finally managed to get it to produce an image somewhat approximating it's capacities Reason for this was that I came in touch with a guy living very closeby, who has the same projector and much more experience and knowledge as to its ways. He came over this evening and went through the setup/convergence process with me, in a summarized fashion.

One problem we were left with was the focus on the green tube - a problem I've had from the start but didn't know how to fix or whether it was my own shortcomings, or something amiss.

The problem is that the green tube is blooming, which shows clearly in for example the point pattern. Enclosed two images, one of the green and one of the red pattern:

(click for larger image)






These pictures were taken immediately after eachother, with all settings the same for both. So if it were contrast or brightness, the problem should show for the red tube as well? (Both are at about 60% by the way) In the pictures it clearly shows how the green image blooms, and also the intense spot isn't centered in the blooming area.

The guy helping me out mentioned that he had a similar problem on a PG before, and that was caused by a faulty chip of this type:





We've taken a look inside and there are five of these in the XG, albeit they end with 220 instead of 020. Then there's another one ending in 240 or 420, I don't recall exactly.


Any spontaneous reactions? Are there any settings that may be off, or could this indeed be caused by faulty electronics? We still managed to get a pretty good image overall, but this is definately something I'd like to dig into and hopefully sort out; it's partially what's been keeping me from trying more and harder on my setup previously: I simply had a feeling I couldn't get proper focus on green and couldn't figure out why, had nothing to compare to.

Hoping that somebody can give me some advice here!

Best regards,
Joris
Uppsala, Sweden

[macgyver655]

I'll assume the lens focus was checked and is not the problem. Then I would ask if the green focus changes with the electronic focus, meaning if you run up and down the scale does the focus on the green get worse and then thats the best you can get it or it doesn't change at all when you run up or down the scale?

[JorisS]

[perisoft]

Does the focus get better if you turn contrast (or green gain) down?

Do the green dots change shape / move when you ramp the focus?

[JorisS]

[stefuel]

Well I can see from the pictures that the astigmation is off. See how it looks like a comet going to the right. You need a better mechanical set up. Also, even with the stig and flare being off, you should be able to get better electrical focus than that. You have other problems to be sorted out.

[JorisS]

[macgyver655]

If your focus setting is not at the end of one side to get it to its best then I'm leaning towards a bad tube.

[JorisS]

[macgyver655]

Take the green lens off or look into the lens with a pair of sunglasses on. Put up a grid pattern and adjust your electronic focus looking mostly at the center, to get it at its best. Is it focused? If not , where on the focus scale are you? Full left, middle, full right or in between?

[Curt Palme]

Do what MacGuyver said. Look into the lenses at high contrast (90 or so) to adjust the electronic focus and astig. Your astig is off for sure, but it also looks like the dot is defocused. Do you know about the focus trimpots that have a slot cut into the card cage? Those are the coarse focus adjustments.

IN all of the NECs I've had here, I've always been able to focus the middle of the screen, assuming the astig adjustments on the necks of the tubes are done correctly. A bad focus board in an XG almost always (from what I've seen) affects the left and right edges only, not the middle. If the middle is out of focus, I'd put my money on an adjustment, either electronic or mechanical) that is not set right.

[Curt Palme]

Do what MacGuyver said. Look into the lenses at high contrast (90 or so) to adjust the electronic focus and astig. Your astig is off for sure, but it also looks like the dot is defocused. Do you know about the focus trimpots that have a slot cut into the card cage? Those are the coarse focus adjustments.

IN all of the NECs I've had here, I've always been able to focus the middle of the screen, assuming the astig adjustments on the necks of the tubes are done correctly. A bad focus board in an XG almost always (from what I've seen) affects the left and right edges only, not the middle. If the middle is out of focus, I'd put my money on an adjustment, either electronic or mechanical) that is not set right.

[JorisS]

Working on it.... here's some pictures, dang hard to get those to be of any use though. Didn't have contrast at 90, guess I'll try again. Sunglasses are necessary though


In words: I definately see a clear difference in focus when sliding from left to right across the bar, with the best focus somewhere between -5 and +20 or so. Further out to either side and it get's worse. I'm having a hard time determining exactly where the best focus is, differences are small in the 0 to +20 range. On the tube I cannot really see the blooming effect, might be due to the small size though?



















On the photo's it appears that green is not nearly as sharp as the red, that's an artifact of the photographing (and higher light output of the green tube?) though. In reality both are about equally sharp from what I can judge.

[macgyver655]

I would now try those focus trimpots in the card cage like Curt said. The middle one should be for the green.


Here's a pic of them: http://www.curtpalme.com/NECXG_Layout1.shtm

[JorisS]

[Curt Palme]

I put the lens on, as it acts as a magnifying glass so you can see the tube face better.

[Curt Palme]

I put the lens on, as it acts as a magnifying glass so you can see the tube face better.

[macgyver655]

Lets try it this way......with the lens on, contrast at 90 like Curt said, looking into the lens with sun glasses on and at the middle of the grid, set electronic focus at mid range......then adjust the green trim pot until you get the best possible focus. Then adjust the electronic focus until you get the best possible focus. Then turn and look at the screen.....and adjust the lens...loosening the wing nut closest to the projector and turning the whole barrel and again looking mostly at the middle of the screen....for the best possible focus. Then snap a pic of the screen with the grid and dot patterns and post it here.

[JorisS]

Allright, will give it a go. Had to take a break and get myself showered

[JorisS]

Ok here goes...

The trim pot didn't require much adjustment, only a minor couple of degrees twisted. After this I still found that the best focus was obtained with electronic focus around 0. Lens didn't require much adjustment, just a little. The edge focus seems to have gotten well worse though.

Anyway, here another bunch of images - taken from different distances, but always red and green with exact same focus on the camera, timer and at the same stationary spot:





















The green is still not nearly as good in focus as the red, particularly visible with the dot pattern. The last image was an attempt with both R and G on, but didn't really work out well. In reality they are more distinguishable. That said I do think it's improved over the pictures from last night though.

On a sidenote, lowering contrast makes the blooming less visible, but it's still there nonetheless. Meaning it's probably not blooming really, but indeed a focus problem? Sliding the green gain across the entire scale hardly gives a noticeable effect - should it? I think when it's on the lowest setting the green loses in intensity vs the red and blue, judging by the dots - when sliding it up to max the dots seem to be somewhat more green dominated. But it's not a very obvious effect.

[macgyver655]

I dont know. I'm having a tough time looking at those pics. The green still looks defocused but to me the red looks defocused too. We are only concerned with the center area for now. The outer area is done later with different adjustments. The CPC is definitely off but it should still focus fairly well. I'm sure it wont hurt to go through the CPC and astig setup and see how it ends up. The focus magnet should be checked as well. I just hate looking at pics. I cant really see whats going on. Maybe its my eyes.......

[macgyver655]

Here is the adjustment procedure. Section 12-3, pages 10-15 thru 18. Maybe you and your buddy can work through this. Read it about 10 times....then read it again about 10 times. Its difficult for 1st timers but easy once you know how.....but i guess thats like anything else..