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picree
Joined: 31 Mar 2006
Posts: 351
Location: Johnson City, TN
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| Posted: Mon May 26, 2008 12:03 pm Post subject: What amplitude for RGB Gain settings? BG808 |
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When setting the preamp voltage on the RGB Gain board what should be the peak to peak reference points for the voltage of 4.0V? is 0V=0 IRE and 4V=100 IRE? Or do you reference the blanking pulse for 0V?
I ask because after setting the 4.0V from 0 IRE to 100 IRE the projector will "tear" if I set the white balance gains any higher than about 75%. So, I wondered if I might be overamping them. Should I reference the blanking pulse for 0V?
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MAIN THEATER: (JVC RS2000; Yamaha UDP-LX500; Yamaha RX-V2400; Lumagen Radiance Pro, Vertex)
SECOND WII-ATER: (BG808; WII; Oppo 971H; Moome external box; BG-DVI transcoder; tse gamma box; Extron)
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Mon May 26, 2008 1:35 pm Post subject: |
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Just turning green little down would probably worked better for your new green tube.
Black should be at 2V, it's adjusted with brightness.
Then black to white 4Vpp (neglecting clamping pulse), when contrast is maxed out!!!
Set also r/b white gains as mentioned in sm before calibration!!!
Did you use fake load (75 ohm resistors) like in sm procedure or were you adjusting neck boards as load? (bit risky)
Other option is set r/b white gains to max and then adjust all output colors to 4Vpp. This is for 1208 driver.
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picree
Joined: 31 Mar 2006
Posts: 351
Location: Johnson City, TN
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| Posted: Mon May 26, 2008 2:01 pm Post subject: |
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Thanks Ile. I will indeed just turn down green preamp a bit. But, I was doublechecking the settings on the various amps. For some reason all preamps were at 3.0Vpp (maybe I set them wrong from before  ). After adjusting them all to 4.0Vpp I did a rough check of greyscale and noticed tearing if I drove R/B gains above about 75% so I thought maybe I had the wrong zero reference.
Yes...I did set all bias/gains as per sm and I used a fake 75 ohm load (you are right...this is a pita). And I checked all three voltages (brightness, contrast, sharpness) and all were set right. I also made sure to use input 1 at 480i (another pita!). As far as I can tell I'm following the sm procedure and all of your advice correctly. It all seems to work except for the tearing at higher gains but I can adjust to stay below that I suppose. The only thing I didn't check was to make sure I had 0.7V on P1 on RGB. But it should be pretty close...
I will do a final check and then turn green preamp down just a bit.
_________________
MAIN THEATER: (JVC RS2000; Yamaha UDP-LX500; Yamaha RX-V2400; Lumagen Radiance Pro, Vertex)
SECOND WII-ATER: (BG808; WII; Oppo 971H; Moome external box; BG-DVI transcoder; tse gamma box; Extron)
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