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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Wed Feb 20, 2013 9:51 pm Post subject: BG 808 and black problem |
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Hello,
I have a BG 808 and I have problem in the dark areas. There are no difference with the shades near black. It seems before that I needed to wait around 30 minutes of warm-up to get the different shades visible, but this evening after 2 hours, I still see every shade as full black. I have Greg Eisemann mod on my Barco but I don't know it is something related to his upgrade. What board could be responsible for that kind of problem?
Brightness = 53, Contrast = 64
Thanks for your help.
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Wed Feb 20, 2013 11:38 pm Post subject: |
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It's probably not a board. You need a test disc like the AVIA to check your projector settings, including gain, black level and G2 settings.
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km987654
Joined: 25 Jul 2007
Posts: 2874
Location: Australia
TV/Projector: Barco BG809s
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| Posted: Thu Feb 21, 2013 1:53 am Post subject: Re: BG 808 and black problem |
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| Corleone88 wrote: | Hello,
I have a BG 808 and I have problem in the dark areas. There are no difference with the shades near black. It seems before that I needed to wait around 30 minutes of warm-up to get the different shades visible, but this evening after 2 hours, I still see every shade as full black. I have Greg Eisemann mod on my Barco but I don't know it is something related to his upgrade. What board could be responsible for that kind of problem?
Brightness = 53, Contrast = 64
Thanks for your help. |
That sounds very much like you're crushing blacks. Are you using any VP if so you might want to try adjusting gamma. If you are not using a VP then you probably need one.
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Thu Feb 21, 2013 8:34 am Post subject: |
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| Curt Palme wrote: | | It's probably not a board. You need a test disc like the AVIA to check your projector settings, including gain, black level and G2 settings. |
I use a test disc Avchd that I found on avsforum. I checked on the the black bars test pattern. I need to raise the luminosity to 65 in order to see bars flashing from level 17 ! And blacks look grey.
My question also is: is it normal that before I have to wait around 30 minutes to see the black bars flashing? Why suddenly now I don't see them flashing after 3 hours?
I just recently changed the Red/Blue cut off and gain values very slightly.
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Thu Feb 21, 2013 8:39 am Post subject: Re: BG 808 and black problem |
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| km987654 wrote: | | Corleone88 wrote: | Hello,
I have a BG 808 and I have problem in the dark areas. There are no difference with the shades near black. It seems before that I needed to wait around 30 minutes of warm-up to get the different shades visible, but this evening after 2 hours, I still see every shade as full black. I have Greg Eisemann mod on my Barco but I don't know it is something related to his upgrade. What board could be responsible for that kind of problem?
Brightness = 53, Contrast = 64
Thanks for your help. |
That sounds very much like you're crushing blacks. Are you using any VP if so you might want to try adjusting gamma. If you are not using a VP then you probably need one. |
I have a HDQ and XD but they are not plugged at the moment. Should I not get decent grey/black shades without any vp?
I don't understand "crushing blacks". Does it mean that no shade of black?
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km987654
Joined: 25 Jul 2007
Posts: 2874
Location: Australia
TV/Projector: Barco BG809s
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| Posted: Thu Feb 21, 2013 8:49 am Post subject: Re: BG 808 and black problem |
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| Corleone88 wrote: | | km987654 wrote: | | Corleone88 wrote: | Hello,
I have a BG 808 and I have problem in the dark areas. There are no difference with the shades near black. It seems before that I needed to wait around 30 minutes of warm-up to get the different shades visible, but this evening after 2 hours, I still see every shade as full black. I have Greg Eisemann mod on my Barco but I don't know it is something related to his upgrade. What board could be responsible for that kind of problem?
Brightness = 53, Contrast = 64
Thanks for your help. |
That sounds very much like you're crushing blacks. Are you using any VP if so you might want to try adjusting gamma. If you are not using a VP then you probably need one. |
I have a HDQ and XD but they are not plugged at the moment. Should I not get decent grey/black shades without any vp?
I don't understand "crushing blacks". Does it mean that no shade of black? |
Crushing blacks means that there is little or no visible difference between IRE levels and so you find it difficult to see detail in dark scenes. CRT projectors will do this. You can improve this by adjusting gamma using your VP. There are several people on this site that have extensive experience at doing this so it would be good if they jumped in but both of those VPs you mention are very capable units.
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Thu Feb 21, 2013 9:34 am Post subject: |
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Ok thanks, I will try and plug the Lumagen. But I am very surprised by what you wrote about CRT projectors. And I am pretty sure that I didn't have this problem before. If it is fixed by the Lumagen, it is fine, but I have the feeling that it will mask a recent and unusual problem on my Barco.
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opv
Joined: 18 May 2010
Posts: 202
Location: Emek Hefer,Israel
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| Posted: Thu Feb 21, 2013 10:03 am Post subject: |
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Did you change anything in the room?
Any new uncovered led in the room, may cause this effect.
The eye shutter opens and the eye can't differentiate between dark gray and black.
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Thu Feb 21, 2013 10:54 am Post subject: |
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Are you sure your sources settings aren't chanced? Can you test source with some other analog display?
There's usually some enhanced black setting or similar in players with hdmi.
Pc could have this kind of issues when drivers are updated or something.
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Thu Feb 21, 2013 10:59 am Post subject: |
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| opv wrote: | Did you change anything in the room?
Any new uncovered led in the room, may cause this effect.
The eye shutter opens and the eye can't differentiate between dark gray and black. |
No, nothing like that. I test in a complete dark room.
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Thu Feb 21, 2013 11:00 am Post subject: |
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| Ile wrote: | Are you sure your sources settings aren't chanced? Can you test source with some other analog display?
There's usually some enhanced black setting or similar in players with hdmi.
Pc could have this kind of issues when drivers are updated or something. |
I have a Pioneer Kuro also plugged to my OPPO-103 and I have black details.
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opv
Joined: 18 May 2010
Posts: 202
Location: Emek Hefer,Israel
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| Posted: Thu Feb 21, 2013 11:04 am Post subject: |
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What is the video chain from the source to the projector?
What do you use for HDMI to analog conversion?
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Thu Feb 21, 2013 11:08 am Post subject: |
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| opv wrote: | What is the video chain from the source to the projector?
What do you use for HDMI to analog conversion? |
OPPO 103->HDMI input card (Eisemann) on BG808.
After I put Greg's modified card, I didn't check if the G2 were correctly adjusted. Maybe that's the reason 
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opv
Joined: 18 May 2010
Posts: 202
Location: Emek Hefer,Israel
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| Posted: Thu Feb 21, 2013 11:12 am Post subject: |
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| Corleone88 wrote: | | opv wrote: | What is the video chain from the source to the projector?
What do you use for HDMI to analog conversion? |
OPPO 103->HDMI input card (Eisemann) on BG808.
After I put Greg's modified card, I didn't check if the G2 were correctly adjusted. Maybe that's the reason |
That could be the problem.
Other than that, does the HDMI input card have enhanced black or other settings you can configure?
If so, that may be the reason for the crushed blacks.
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Thu Feb 21, 2013 1:07 pm Post subject: |
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| opv wrote: |
Other than that, does the HDMI input card have enhanced black or other settings you can configure?
If so, that may be the reason for the crushed blacks. |
No configuration on this HDMI card
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stridsvognen
Guest
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| Posted: Thu Feb 21, 2013 2:19 pm Post subject: |
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Try run RGB pc level 0-255.. Remember douing that with my HD furry 3 to get that one to work. But with moome i had to go with video level.
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Thu Feb 21, 2013 6:43 pm Post subject: |
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After looking at the G2 procedure, I just realize that I have RGB amp from a BG 800 (no green led) that I bought to avoid the streaking problem. I still have the original ones with the green led. So,if I put back the original ones to adjust the G2 (green led) and put back the ones from the BG 800, would it be ok?
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Thu Feb 21, 2013 8:29 pm Post subject: |
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I found a post from Ile explaining how to adjsut the G2 when there is no green led. I raised the G2s values (I stopped raising when I started to see the rasters). So now I see the black bars flashing with a luminosity of 61). Should I still raise the G2 values?
I follow that "Select 6500K from color menu.
Set brightness to 50 and contrast to zero. Project video black picture and adjust G2 pots from G2 board until you just barely see rasters gloving when you look in to tubes."
But what is "barely glowing"? It is when you start seeing the raster or the raster has to "shine"?
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km987654
Joined: 25 Jul 2007
Posts: 2874
Location: Australia
TV/Projector: Barco BG809s
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| Posted: Thu Feb 21, 2013 10:23 pm Post subject: |
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| Corleone88 wrote: | | After looking at the G2 procedure, I just realize that I have RGB amp from a BG 800 (no green led) that I bought to avoid the streaking problem. I still have the original ones with the green led. So,if I put back the original ones to adjust the G2 (green led) and put back the ones from the BG 800, would it be ok? |
I am surprised the BG800 50mhz amps are operating as they require 230v and the 808 will supply 210v for the 75mhz amps or do you mean these are from an 801 as that unit had 75mhz amps.
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Fri Feb 22, 2013 7:53 am Post subject: |
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| Corleone88 wrote: | So now I see the black bars flashing with a luminosity of 61). Should I still raise the G2 values?
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If that luminosity setting from player or scaler, you should set that to default (50 ???) before G2 settings.
Or if you mean projector brightness, that should be around 50. So G2 is bit high right now, but it doesn't matter because you compensate with brightness.
| Corleone88 wrote: | | But what is "barely glowing"? It is when you start seeing the raster or the raster has to "shine"? |
It's not that accurate, because you adjust final black level with brightness. It's more important that you set all colors to about same level, this is also fine tuned with custom black level from menu.
| km987654 wrote: | I am surprised the BG800 50mhz amps are operating as they require 230v and the 808 will supply 210v for the 75mhz amps or do you mean these are from an 801 as that unit had 75mhz amps.
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He must mean 801 amps (762173), those are same that 801s/808 amps (7621735 / 7621736) but without ABL.
So no streaking problem. 
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