Can anyone help me explain this shadow on my BG1209/2 - AVS Forum
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post #1 of 4 Old 08-11-2011, 09:46 AM - Thread Starter
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As seen on the picture.



This is with only the green CRT on. (Red and blue covered)
I noticed this small shadow to the right of the original signal. It shows up when I have an all white desktop (on the HTPC) and open a small window with black text on a light background. But if I change the desktop background back to black, it´s gone.
Did the same test on the blue and red CRT but can't see it there. Only on the green.

Sorry about the PQ its zoomed in and the camera had a hard time focusing in the dark, but it still shows the problem.

Could this be an early sign of a power supply problem?, (I'm thinking it requires more power to show the all white background, rather than the black background) or what are we looking at.?

The setup is:
Barco BG-1209/2 (1997 model) with about 1.700 hours
John's BG-DVI interface on port 3
HTPC. With NVIDIA GT440 (Vista)
Rez: 1280 x 720p at 71.928hz

Thanks
HenrikM
LL

A Dane living in Sweden
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post #2 of 4 Old 08-12-2011, 03:33 AM
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Ringing is caused by video signal bath. Both pictures have overshoot in video signal after black object, with white back ground it's just easier to see because overall gain is limited and text box is darker.

Port3 board have pretty much peaking in signal path, I guess that is causing that over shoot after black object. Port5 should have little better result in your projector and in newer 1209s difference is even bigger.

When I was experimenting with my BG1200 I found out that removing peaking components from signal bath attenuated ringing effect and made picture sharper. I also chanced higher BW transistors at same time, so that much peaking was not needed.

RGB channels have different amount of peaking and If I remember correct blue channel had it most, but it's hard to see from blue because it's soft anyway. Then comes green and red had it least.
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post #3 of 4 Old 08-24-2011, 01:59 PM
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Yes port 3 is terrible do not use it.

Try one of our internal HDMI cards it will give you a 75% sharper image and no ring.

Gregory C. Eisemann Senior Electrical Engineer, Satcom Engineer, Opnet Engineer, Network Engineering, Satellite Engineering
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post #4 of 4 Old 08-24-2011, 09:26 PM
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Greg never misses an opportunity. How about posting some comparative test images so that we can see the improvements offered by your mods.
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