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Joachim
Joined: 22 Oct 2007
Posts: 10
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| Posted: Fri Dec 21, 2007 8:07 am Post subject: Light horisontal streaks next to bright objects |
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Hi!
I'm getting some light streaking next to high contrast areas with my Barco Data 801s. A dark background with light objects, say stars or the mouse pointer create weak brighter horisontal lines.
I'm running it from my computer through an "Inline 2160" VGA->RGB composite sync interface, and with bnc to input 5. I tried switching the BNC cable, as I've understood this is mainly a cabling problem. Do you think it would be better to use Powerstrip and disconnect the Interface box? I used PowerStrip with my old VideoGrade projector, but I cannot seem to make it work with the barco.(?) That's why I use the Inline box.
I've also considered making a cable for the 9pin video input, as some say it is better than BNC. However to get that working i first need to figure out how to configure PowerStrip.
The projector has Mint tubes and about 1500hrs on the clock.
The problem is not extreme, but in some dark movies it is slightly disturbing at times.
What else could it be? Dried out capacitors somewhere?
Happy holidays!
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Dave Lister
Joined: 16 Jan 2007
Posts: 436
Location: Adelaide, South Australia
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Fri Dec 21, 2007 11:09 am Post subject: |
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Port5 need negative sync polarity, that can be set from Powerstrip or you can use that Inline 2160 box for it. That box probably also have line driver stages for rgb, so it's good thing if you have long cables.
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Joachim
Joined: 22 Oct 2007
Posts: 10
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| Posted: Fri Dec 21, 2007 6:26 pm Post subject: |
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| Ile wrote: | You are not alone with this problem.
http://www.avsforum.com/avs-vb/showthread.php?t=512219&highlight=barco+streaking+survey
It have been seen in every Barco model that use 7621735 or 7621736 75MHz rgb amps, but for some reason not in every unit.
In my two low hour 801s streaking was in every input and with many different sources. It was not dryed cap or chanced adjustment in board level. After lots of tests I found out that only removing ABL circuit removes streaking.
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Excellent info, thank you. This was the exact answer i was looking for. I think I'll try virst with negative sync and a cable to input 5, if that doesnt work I'll try the ABL-ectomy 
What does the ABL Circuitry do?
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Joachim
Joined: 22 Oct 2007
Posts: 10
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| Posted: Fri Dec 21, 2007 6:36 pm Post subject: |
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| Dave Lister wrote: | | VGA is RGB, just use a VGA to 5 BNC breakout cable, if the PJ has only 4 BNC inputs for RGB then use a T connector for the H and V sync to connect them both to the combined H/V sync connection that is used with 4 RGB inputs. |
Yep, I tried that directly from the computer to the 5 BNC input 5 of the Barco. However whatever sync and frequency I set in Powerstrip, I couldn't get the PJ to accept the signal, so I had to revert back to my interface box to make it work. I was wondering if the interface box that "converts" from VGA to 5BNC and fixes sync and so on could be the source of the streaking. But since i cannot test without it i can´t rule it out...
I know the VGA is RGB, i made a simple VGA to SCART RGB-cable for my videograde PJ before, and I managed to make it reach 1024*640i Widescreen and accept that as "PAL" Gotta love powerstrip
EDIT:
After reading the old thread on streaking, while drinking a glass of Lindeman's red wine, stalling a party I'm supposed to go to, my GF is gonna kill me if she finds out why I'm late  ) I just wanted to say that I don't seem to get any streaking on the menus or internal patterns at all. Not that I have been able to se. Nothing as bad as the green menu pic supplied by one of the members in the streaking thread. An furthermore, thank you for all your help, I appreciate being here. I think this board will be my new start-page Thanx guys, this seems like a really friendly and skilled community!
EDIT2: Thanx for the info on the T-connector, I didn't know it was that easy to hard-hack to a composite sync. Cool
Last edited by Joachim on Fri Dec 21, 2007 7:20 pm; edited 2 times in total
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Fri Dec 21, 2007 6:49 pm Post subject: |
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| Joachim wrote: | | What does the ABL Circuitry do? |
It should compensate tube wear and keep color balance constant. But basically it causes streaking, lower BW and cause flickering to full white picture. 
I think it's designed for commercial use, where projectors was running 24/7 and tubes was wearing much faster.
In Sony projectors similar AKB system is also causing bright line to top of every tube.
| Joachim wrote: | | However whatever sync and frequency I set in Powerstrip, I couldn't get the PJ to accept the signal, so I had to revert back to my interface box to make it work. |
Do you have Nvidia drivers installed? Those have had weird sync problems with older Barcos lately. Try about year old drivers...
Last edited by Ile on Fri Dec 21, 2007 7:18 pm; edited 1 time in total
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Joachim
Joined: 22 Oct 2007
Posts: 10
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| Posted: Fri Dec 21, 2007 7:17 pm Post subject: |
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| Ile wrote: |
| Joachim wrote: | | However whatever sync and frequency I set in Powerstrip, I couldn't get the PJ to accept the signal, so I had to revert back to my interface box to make it work. |
Do you have Nvidia drivers installed? Those have had weird sync problems with older Barcos lately. |
Hi! A bit of cross posting here sorry, I need to be more trigger-happy on the Reload
Thanx for the info on the ABL. Seems unnecessary for me. This means the 800 would be clear of this problem since it doesnt have ABL if I'm correctly informed. The ABL-ectomy seems a bit hard to reverse, and would require some nice de-soldering skills I'm not sure I have. Sure I've been de- and re-soldering surface mounted resistors at times, but that was agonizing (I modded a GF2 into a quadro, and then found the softmod. haha. You live you learn... ) Anyway, back to your original question, I have a Radeon 9800 card, which was needed to output composite sync for my Videograde Nordmende Projector. (Which freaked out on me and started lowering G2 way too much on bright signals, causing me to have to up the G2's considerably causing spot burn on shutdown ;( ) So that's why I upgraded to a Barco 801s. It's like night and day. However the Nordmende had lots of faults, but no streaking whatsoever. And streaking does take something away from the IQ (Image Quality). I wonder if I'm brave enough to go get tha ABL de-ABL'ized. I live in Jakobstad, Finland. As for helping me... Ehm...
(It might be tha wine talking, but It's been a long time since I felt so helped and welcome in a forum. Thanx guys! I know Curt is a nice guy, he helped me with the Nordmende G2 problem!)
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Fri Dec 21, 2007 7:28 pm Post subject: |
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I'm also in Finland Jyväskylä and can forward my test amp to you after one other friend have tested it in his 808s.
PM your address...
Yes you are right 800 are free from streaking, but those have lower BW rgb amps.
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Joachim
Joined: 22 Oct 2007
Posts: 10
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| Posted: Fri Dec 21, 2007 7:51 pm Post subject: |
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| Ile wrote: | I'm also in Finland Jyväskylä and can forward my test amp to you after one other friend have tested it in his 808s.
PM your address...
Yes you are right 800 are free from streaking, but those have lower BW rgb amps. |
Excellent, It would be interesting to test. I just bought this PJ from Helsinki If the 800's are free from streaking, it must be the ABL. Are you sure the 808 board will fit the 801? Again thanx a lot, I'll get back to you. I must run to the party now
Thanx again. This place rocks!
God Jul ja Hauskaa Joulua and Merry Christmas !
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Fri Dec 21, 2007 10:23 pm Post subject: |
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| Joachim wrote: | Excellent, It would be interesting to test. I just bought this PJ from Helsinki If the 800's are free from streaking, it must be the ABL. Are you sure the 808 board will fit the 801? Again thanx a lot, I'll get back to you. I must run to the party now
Thanx again. This place rocks!
God Jul ja Hauskaa Joulua and Merry Christmas ! |
That "test amp" is originally from my BD801s, part number is R7621735 and those look like this
http://mpmods.com/images/R7621735.jpg
808 and Data 808s use same board, Graphics 808s have newer one peace neck card.
Pre series 801s had older different looking R762173 amplifiers, same as in 801 (non s). Those don't have ABL and streaking problem. 800 had little different design...
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