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Discussion Starter · #1 ·
I've only had this projector set up for about a week now and I'm still learning how to set it up properly. My problem is I seem to have a blue halo on white objects I can't get rid of. Convergence is ok. It gets worse when contrast is up high but even with contrast down lower I can see it. I tried turning blue gain down to zero and that pretty much eliminates it but colors don't seem right, it needs some blue gain. I even tried doing an electronic blue focus adjustment, that seems ok. Any suggestions or help on this ?


Thanks,

Rod
 

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About the only thing you can do is keep the contrast down, I managed to play with the bias and G2 on the blue CRT and reset the other tubes for a good 6500K picture. I am hoping that when I get my HI Power screen in I can get some of the contrast back. The other thing is that the blue tube is the one that fails first you might be in the market for a new tube.
 

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Discussion Starter · #4 ·
All three tubes are new and recent VDC rebuilds. I have tried tried adjusting the Dyn. astigmatism. It's an electronic adjustment on my projector. Not sure if there'a a manual adjustment also. I think the astig adjustment may not be working, I'm not sure. But I can see no difference in the shape of the dots when I adjust from 0-100. On my last projector (701S) the astig adjust was manual but I remember seeing a definite difference in the shape of the dots as the yolk was turned. Maybe I'm doing this wrong. In the service menu I highlight Dyn Astigmatism and adjust each color, but I can't see a difference.


Rod
 

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Rod,


Who did the tube swap out? When this was done the 2-pole/4-pole (astig/flare) mechanical adjustments on the tube's neck should have been performed. Blue is always the hardest to do since its hard to see blue.


I believe the service manual should have the adjustment proceedure in the CRT replacement section and it probably starts out by having you set electronic focus and astigmatism to their null positions.


In my line of thinking, I would redo the mechanical focus assy adjustment, the 2-/4-pole adjustments, and the electronic adjustments and if the spot focus can't be tightened up then maybe the tube is bad. I understand that the VDC tube rebuilds aren't 100% perfect every time.


Mark
 

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Hmmm... I guess I would also try swapping the blue and green output amps (neck boards) and make sure your blue amp isn't going bad. If you're seeing the blooming/halo on both sided of images they're probably okay and its still might be a spot focus issue though, but its something else to consider.


Mark
 

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Discussion Starter · #7 ·
Mark,


Thanks for the info. Darrell at Hammerhead Tech did the tube swap out. I will check with him to see if he did an astig/flare mechanical adjustment.


I've been trying to find the manuals for the 1209, but no luck so far. Only have 1209S owners manual, but I understand they are quite different. It sounds like that may be the problem though.


I am seeing the blue halo on both sides of the image, and its only on light colored or white images that I can see it. No experience on swapping neck boards. You make it sound easy though, if I can locate a service manual I would try it if necessary. I am leaning toward the astig/flare adjust though.


Thanks,

Rod
 

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Hi Rod,

I just retubed my pj (Marquee 8500) with VDC rebuilt,I had the same

problem with blue tube.

Definetly it was a flare-astig issue.

If it is so evident to note it as a blue halo on a clear field,it should'nt

be difficult to note it in a crossatch test pattern,the blue line should

look thicker that red and green,so the points.

If this is the case and you're not able to fix it with focus,then go the

check the flare and astig.

Mauro
 

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Discussion Starter · #9 ·
Mauro,


I definitely need to learn how to do mechanical adjust flare/astig. That is the place I must start. Must get my hands on a BG1209 service manual. They must be rare, I can't find one.


Thanks,

Rod
 

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You might need to replace the blue tube again. Darrell seems pretty good in setting these sets up, so if Chico, Ca is close to you, you might want to take it back or get one of his staff to come over...


Curt
 

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Discussion Starter · #11 ·
Curt,


Thanks, I will contact Darrell. Don't want to send it back though. It's ceiling mounted and what a hassell that would be. Is it possible to remove the tube and replace while its still ceiling mounted? I'm hoping that won't be necessary. I will do it but I want to explore all other possibilities first. Chico is about 6 hour drive north of me. If only I could find a Barco expert in my area to come take a look. That's what I really need. Any takers ?


Thanks,

Rod
 

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Discussion Starter · #12 ·
OK, I think now it's not a bad blue tube - I hope. Please tell me what you think about this observation.


On a grid where only blue is showing (such as Dyn Astig or focus) , when I increase the contrast, the horizontal blue lines get REALLY fat and blurry, but the vertical blue lines stay sharp. Brightness level has no effect on size of lines.


If I put up a green grid, the horizontal and vertical lines get fatter proportionally, but not nearly as severely as the blue.


On a red grid, both horizontal and vertical lines stay really sharp no matter what contrast level.


What do you think is my problem? It must be a mechanical setup issue, I think. Why would horizontal lines on blue grid get fatter and blurrier and vertical remain sharp?


Thanks for any help you can offer.


Rod
 

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Flare and astig are out,

If you look to the dots they are not round but very

alongated ovals.

I know nothing about tubes assembly of your pj,

but it should not be so dissimilar from Marquee.

You have to reset the blue tube starting from flare and astig

(CPC magnets 2 and 4 poles),doing that the raster will move

and you have to re-adjust it

(read Holy Focus of Guy Kuo)

and read also my PM

Mauro
 

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Discussion Starter · #14 ·
Mauro,


I think you are probably right. Only the red dots look round. Blue and green are very elongated. The electronic Dyn Atstig adjustment makes liitle difference in the shape of the dots, it must be for minor adjustmemts. I have only tried this adjustment at 720P though, and as I understand it must be done with a composite signal, not sure why. I guess I'll have to try the 2 pole/4 pole adjustment. I'm a little nervous about doing this though since I have not done it before. There's always a chance I could make it worse but I can't live with it this way. More research and reading ahead for me.


Thanks,

Rod
 

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Discussion Starter · #15 ·
I just realized something. When I first fire up the projector, the blue gun comes on before the red and green. Does this mean it is getting more voltage and that the G2 is set too high on the blue ? If so, can I simply turn down the Blue G2 a little until the blue light goes off ? Or am I making this too simple ?


If I can , what equipment do I need to do this and is the adjustment near the LEDs ?


Rod
 

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The blue gun firing off first doesn't mean anything.

If your dots are elongated now, you aren't going to make it any worse.

First set your electronic astig back to the middle point, then overfocus the gun your working on (all the way) you may also need to increase contrast to see the dots better. Then at the back of the tube, you'll see the CPC magnets, there are two pair you can adjust, both have little thumb wheel adjustments that will rotate the magnet pair in opposite directions, plus you can spin the magnet pair around the tube neck simply by pushing the thumb wheel around without twisting it.

It's been two weeks since I did the 1209, but I THINK the front pair adjusts the Astig, and the rear pair adjust Flair. Someone may come in here and help with that.

If your dots are oblong in the horizontal plain, then you want get them in more of a diagonal plain, you do this by rotating the magnet pair as one...pushing the thumb wheel around the tube neck, once you get the oblong dot in the diagonal plain, then rotate the thumb wheel (this spins the magnets in opposite directions) and you'll see the oblong dot start to "round out"...you will see that moving the magnets as a pair changes the dot's adjustment plain, and rotating the magnets separately adjusts the shape within the plain, so it's a combination of both. Use the center dots as your reference

After Astig is set, then underfocus and adjust the other pair of magnets to center the core in the flair. Then go back and make sure Astig is still correct...you may have to go back and forth a couple times.

Check focus when your done. (should be ok)

BE VERY CAREFUL INSIDE, HIGH VOLTAGE IS PRESENT!!!


Hope I didn't confuse you to much...it's late and I may be babbling:eek:
 

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Discussion Starter · #17 ·
Kenny,


Thanks a lot for the specific info. One question though, is it necessary to feed the projector a composite signal for this procedure, or can I use the output from the scaler set to 720P ?


Thanks,

Rod
 

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Discussion Starter · #18 ·
Last night I finally summed up the courage to try what most of you have been telling me about adjusting the astig/flare using the CPC magnets adjustment. And voila,the blue halo is gone!


Many thanks to all of you, especially KennyG. Your specific info on twisting the thumb screws on astig/flare did the trick. As I twisted the screw on the back magnets to the right the blue dot went from a vertical line to a circle (although I had to turn it all the way to the end of the adjustment range for best results). I can now turn the contrast all the way up and the blue doesn't bloom at all and I have a nice tight blue grid now with thin horizontal lines instead of fat ones.


However, I may have pushed my luck too far because when I tried to adjust the green in the same manner, I think I made it a bit worse. Oh well, at least I feel comfortable now to go back in and try it again. Hey this is kind of fun !


Thanks a lot,

Rod
 
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