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Discussion Starter · #1 ·
Up late here trying to figure out why there's a small amount of light output from my tubes on all-black (Barco 708s)? At first, I thought it was my brightness or input, but I killed my sources, and the tubes are still slightly luminous. Turned brightness and contrast down to 0, no change. The full tube shape is discernible on my wall with all lights out on black/off, confirmed when I wave my hand in front of the lenses.


Does anyone know what might be happening here? It's not normal for tubes to emit anything on all-black, is it? I've watched a few films on this thing already, so it's not necessarily a deal breaker (yet), but I was under the impression that a black source should have ZERO light output with CRT.


I appreciate any input -- hope someone can help!

 

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Quote:
Originally Posted by Cinenut /forum/post/12975831


Up late here trying to figure out why there's a small amount of light output from my tubes on all-black (Barco 708s)? At first, I thought it was my brightness or input, but I killed my sources, and the tubes are still slightly luminous. Turned brightness and contrast down to 0, no change. The full tube shape is discernible on my wall with all lights out on black/off, confirmed when I wave my hand in front of the lenses.


Does anyone know what might be happening here? It's not normal for tubes to emit anything on all-black, is it? I've watched a few films on this thing already, so it's not necessarily a deal breaker (yet), but I was under the impression that a black source should have ZERO light output with CRT.


I appreciate any input -- hope someone can help!





your G2 levels probably are a little high.


you have 2 pots on the side , one G2 and one focus


there's a LED that can be used to adjust the G2.




Michael
 

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Quote:
Originally Posted by nidi /forum/post/12976130


your G2 levels probably are a little high.


you have 2 pots on the side , one G2 and one focus


there's a LED that can be used to adjust the G2.




Michael

I'm not a Barco expert but I do know that tweaking your G2 levels can put you in worse shape than you are now. Just be careful or you might end up ruining your grayscale, color, etc.
 

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Quote:
Originally Posted by dropzone7 /forum/post/12976158


I'm not a Barco expert but I do know that tweaking your G2 levels can put you in worse shape than you are now. Just be careful or you might end up ruining your grayscale, color, etc.

I think 'ruining' is a relative term here. If you can stick a grey ramp on there, you can screw with stuff all you like and if you have eyeballs which work you can get stuff pretty close quite easily. I'm sure it won't be ISF-whatever, but it'll be a hell of a lot better than jacked up black levels.
 

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Quote:
Originally Posted by PeriSoft /forum/post/12977887


I think 'ruining' is a relative term here. If you can stick a grey ramp on there, you can screw with stuff all you like and if you have eyeballs which work you can get stuff pretty close quite easily. I'm sure it won't be ISF-whatever, but it'll be a hell of a lot better than jacked up black levels.

I'm sure you are correct. I'm just so conditioned to not touch pots in these projectors because everything I read says don't mess with them if you don't know what you are doing. I would count myself as one "not knowing what I'm doing". If I can't adjust it with the remote then I pretty much leave it alone. For that reason I'm sure that mine needs a technicians touch to look any better than I can get it.
 

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Quote:
Originally Posted by dropzone7 /forum/post/12978069


I'm sure you are correct. I'm just so conditioned to not touch pots in these projectors because everything I read says don't mess with them if you don't know what you are doing. I would count myself as one "not knowing what I'm doing". If I can't adjust it with the remote then I pretty much leave it alone. For that reason I'm sure that mine needs a technicians touch to look any better than I can get it.

On the other hand, if you never try it you'll never *get* to know what you're doing.


I was completely new to CRT projectors this past June; now I'm comfortable tweaking astig, swapping tubes, etc. Naturally I didn't know how to do any of that at the beginning - and if I hadn't done all of it anyway I still wouldn't!
 

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Quote:
Originally Posted by PeriSoft /forum/post/12978099


On the other hand, if you never try it you'll never *get* to know what you're doing.


I was completely new to CRT projectors this past June; now I'm comfortable tweaking astig, swapping tubes, etc. Naturally I didn't know how to do any of that at the beginning - and if I hadn't done all of it anyway I still wouldn't!

I'm too chicken I guess.
I'm pretty happy with the way mine looks right now. Luckily my astig was in pretty good shape when I got the projector.
 

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I'm middle ground,


I've swapped tubes, changed glycol, and machined new tube mounting plates but I won't do the magnetics, I was zapped a few times swapping neckboards and don't want to get anywhere near that stuff again
 

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Just mark the position of the pots. Use something that will allow you to get the setting back to where it was originally.


You can still screw up settings with the remote, even something as simple as contrast and brightness needs to be done correctly, let alone going into the service menu. I would bet 95% of people out there do not know how to set contrast or brightness.


Just make sure you understand what that adjustment you are going to mess with does and how it effects things, at least this way you will know if what you are going to do will be what you want to do.


Deron.
 

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Quote:
Originally Posted by deronmoped /forum/post/12979515


I would bet 95% of people out there do not know how to set contrast or brightness.

Yeah, I am one of them! I have Avia and DVE as well as some other setup discs but I truly don't understand what I'm looking at. I have a basic understanding of how it works but am never really sure if I have done it correctly.
 

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Discussion Starter · #12 ·
Well, it's a relief to know that there's even something to tweak -- I was worried for a moment that this was a tube issue beyond repair. I've read all the warnings about G2 myself, so if I do attempt an adjust, I will be enormously careful and mark my tracks. Thanks for your help, guys.


P.S. Just an aside, how much would a pro calibration run me if I were to ever consider it here in Seattle? (Not that I don't want to learn, I'm just curious!)
 

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Quote:
Originally Posted by Cinenut /forum/post/12980976


P.S. Just an aside, how much would a pro calibration run me if I were to ever consider it here in Seattle? (Not that I don't want to learn, I'm just curious!)


You can count on about $85-$100/hr. plus travel and expenses. That's the range I have been quoted anyway. It really helps if you have a tech close by to save on the expenses. The hourly rate is worth every penny I'm sure but the travel, hotels, etc. can add up in a hurry if they are not in your backyard. You might check Curt's site for the referral list he has there.
 

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Discussion Starter · #14 ·
Stupid question -- could someone explain the difference between the top 3 (covered/black) and bottom 3 (RGB colored) G2 adjustment screws? I assume one is focus and the other is brightness, but which is which? (I love to tweak display calibrations on my LCD monitors, so I hope G2 is SOMEWHAT similar...)

Quote:
Originally Posted by dropzone7 /forum/post/12981042


You can count on about $85-$100/hr. plus travel and expenses. That's the range I have been quoted anyway. It really helps if you have a tech close by to save on the expenses. The hourly rate is worth every penny I'm sure but the travel, hotels, etc. can add up in a hurry if they are not in your backyard. You might check Curt's site for the referral list he has there.

Hmm, that could go beyond my budget, I'm afraid... I could spare around $150 at the moment, but I guess I ought to just buckle down and learn this stuff instead.
 

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Discussion Starter · #15 ·
Haha -- so get this... Turns out my 'ghost light' was actually the indicator LEDs on the front of my unit. Finally realized this obviousness by popping on the lens caps instead of waving around a velvet swath. The LEDs just happen to paint a long, curved line along my bottom wall, almost looking like a tube face.


Glad I didn't touch the G2...



Why did Barco make those things so darn bright? Is it OK to cover them up with a trimmed piece of tape or velvet while not in setup mode?
 
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