Post by gjaky on Feb 10, 2018 15:53:36 GMT -5
This is something I'm struggling from the very first time since I have my "new" 2010 VDC Marquee 9500LC, as forefront the unit came from a TOFT simulator, yes, and has ~16000hrs usage with ~8000hrs on tubes.
So there is some sort of interference seen on the projected picture, the effect very much looking like 480i with massive scanlines, but these "scanlines" are not synced to either line (H or V) frequency so it has a definite waving effect too, and are present on any resolution. But this noise onlyappears to affect the vertical plane, but not the Horizontal.
I've easily narrowed down that this is not coming from the video chain as I've tested with the same results the original VDC VIM+VNB combo, the classic line up (02p VIM + ...3339 VNB) and of course with both my mod boards.
I've had once similar on a NEC 9PG xtra and there the "noise" came from the dyn. astig driver.
Long story short, I found that the noise only appears on screen when the convergence yoke is plugged in. The most obvious idea is to recap the whole CVA, but it is not that funny to think about it, so let's chat a little bit first.
The board does employ Rubycon caps just like the ancestors, they all look good, although I haven't pulled a single one to measure, so in fact they can be bad, but why only vertical then? Also, isn't there some grounding issues around those boards, if so what was the deal?
So there is some sort of interference seen on the projected picture, the effect very much looking like 480i with massive scanlines, but these "scanlines" are not synced to either line (H or V) frequency so it has a definite waving effect too, and are present on any resolution. But this noise onlyappears to affect the vertical plane, but not the Horizontal.
I've easily narrowed down that this is not coming from the video chain as I've tested with the same results the original VDC VIM+VNB combo, the classic line up (02p VIM + ...3339 VNB) and of course with both my mod boards.
I've had once similar on a NEC 9PG xtra and there the "noise" came from the dyn. astig driver.
Long story short, I found that the noise only appears on screen when the convergence yoke is plugged in. The most obvious idea is to recap the whole CVA, but it is not that funny to think about it, so let's chat a little bit first.
The board does employ Rubycon caps just like the ancestors, they all look good, although I haven't pulled a single one to measure, so in fact they can be bad, but why only vertical then? Also, isn't there some grounding issues around those boards, if so what was the deal?
