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Corleone88
Joined: 09 Dec 2006 Posts: 443 Location: France
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Link Posted: Tue Feb 20, 2018 7:21 pm Post subject: Issue with green |
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Hello,
I have a rather odd problem on the green with my BG 1209s. If I display a green grid (1080p72Hz signal), I have the horizontal lines looking much more brighter than the horizontal lines. Lum/Contrast = 50. This problem occurs only on the green. Thanks for your help.
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Curt Palme CRT Tech
Joined: 08 Mar 2006 Posts: 24296 Location: Langley, BC
TV/Projector: All of them!
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Link Posted: Tue Feb 20, 2018 7:29 pm Post subject: |
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Can you try an external test pattern? I've never seen this before. What if you use a lower resolution?
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Corleone88
Joined: 09 Dec 2006 Posts: 443 Location: France
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Link Posted: Tue Feb 20, 2018 8:24 pm Post subject: |
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Here is a picture with a Lumagen test pattern (1080p60Hz this time): same thing apparently
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Curt Palme CRT Tech
Joined: 08 Mar 2006 Posts: 24296 Location: Langley, BC
TV/Projector: All of them!
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Link Posted: Tue Feb 20, 2018 8:41 pm Post subject: |
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Try a lower resolution for fun. I am a bit stumped though.
Also try swapping CRT neck boards between tubes.
Check the 17.5 volt test point on the SMPS to make sure it's accurate.
Pull the convergence tray from out of the front (power cord unplugged) and power back up to see if that fixes it. (I doubt it)
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Corleone88
Joined: 09 Dec 2006 Posts: 443 Location: France
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Link Posted: Tue Feb 20, 2018 8:49 pm Post subject: |
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With 1080i60, Here is the results with Lumagen test pattern for each color (notice the "fat" horizontal green line):
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Corleone88
Joined: 09 Dec 2006 Posts: 443 Location: France
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Link Posted: Tue Feb 20, 2018 9:25 pm Post subject: |
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It seems that it is a bit more complicated to swap neck boards than with a 808. Do I need to remove the big part from the end of the tube to remove the neck board?
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Curt Palme CRT Tech
Joined: 08 Mar 2006 Posts: 24296 Location: Langley, BC
TV/Projector: All of them!
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Link Posted: Tue Feb 20, 2018 9:31 pm Post subject: |
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Just loosen the two screws that you see that go into the black heat sink at the top, then the CRT socket wiggles off, and the wiring disconnects at the top heatsink, and the other one at the motherboard.
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Corleone88
Joined: 09 Dec 2006 Posts: 443 Location: France
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Link Posted: Tue Feb 20, 2018 10:08 pm Post subject: |
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Is it the neckboard to swap ? The neckboard seems to come with the socket. So I need to swap the neckboard+the socket.
I have one wire to the motherboard but also two black wires remaining and going to the tube.
About the 17.5V point to check is it labelled J36?
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Curt Palme CRT Tech
Joined: 08 Mar 2006 Posts: 24296 Location: Langley, BC
TV/Projector: All of them!
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Link Posted: Tue Feb 20, 2018 10:51 pm Post subject: |
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Yes, swap that whole assembly over between tubes.
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Corleone88
Joined: 09 Dec 2006 Posts: 443 Location: France
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Link Posted: Wed Feb 21, 2018 9:13 am Post subject: |
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Well, I swaped the neck boards: no change. I checked J36 for the 17.5V: I got 17.51V. And I removed the convergence tray: no change.
Which card manage the green signal?
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Curt Palme CRT Tech
Joined: 08 Mar 2006 Posts: 24296 Location: Langley, BC
TV/Projector: All of them!
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Link Posted: Wed Feb 21, 2018 2:47 pm Post subject: |
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I'd change the two video boards, the V board, H board. The V and H boards have some circuits on them that could affect the video signal, but I'd suspect the video boards first.
I've got the boards at $15 each (4 minimum) plus shipping.
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Corleone88
Joined: 09 Dec 2006 Posts: 443 Location: France
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Link Posted: Wed Feb 21, 2018 3:02 pm Post subject: |
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I have some replacement cards but I need to check if I have these. About the video cards, one (the port 3) has a HDMI connector (from Greg Eisemann, I took it from my former BG 808).
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Corleone88
Joined: 09 Dec 2006 Posts: 443 Location: France
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Link Posted: Wed Feb 21, 2018 5:02 pm Post subject: |
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I had a replacement for the rgb video boards and it seems to fix the problem. The weird thing is that the replacement card does include a small module (electronic card with some yellow wires) and I do not know what it is for. Here is a picture (the module R76274S or R762745 is on the bottom left):
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Curt Palme CRT Tech
Joined: 08 Mar 2006 Posts: 24296 Location: Langley, BC
TV/Projector: All of them!
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Link Posted: Wed Feb 21, 2018 7:56 pm Post subject: |
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I think it may be for contrast modulation, I can't remember.
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Corleone88
Joined: 09 Dec 2006 Posts: 443 Location: France
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Link Posted: Thu Feb 22, 2018 6:56 am Post subject: |
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Anyway, thanks a lot for your help Curt
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barclay66
Joined: 27 Jun 2011 Posts: 1291 Location: Germany
TV/Projector: Marquee 9500 Ultra
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Link Posted: Thu Feb 22, 2018 9:55 am Post subject: |
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Hi,
The add-on board is a R762745 - QUAD decoder+Comb_Filter. This is only necessary, if You want to feed other signals than RGB (e.g. Composite Video or S-Video). You should be able to transplant the add-on board to the video board You want to be using...
Kind Regards,
barclay66
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Corleone88
Joined: 09 Dec 2006 Posts: 443 Location: France
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Link Posted: Thu Feb 22, 2018 9:59 am Post subject: |
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Ok thanks. I think this shouldn't be necessary I think
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