choosing a monitor
D9400 color and scanline questions
Posted: May-16-2015 5:15 PM
Join Date:May-16-2015
Post: 4

I purchased and received an X-Arcade machine that came with a D9400 WG monitor. I believe that's the model (the number printed on the back comes up only on Alibaba).

In any event, when I received it, all the vertical green pixel rows were illuminated. No amount of OSD (on screen display) tweaking of Green or anything else fixed it.

Out of ideas, I tweaked the HV Adjust on the daughterboard. I have no idea what that does (other than adjust high voltage I assume), but was able to turn it "up" enough that I could get rid of the green lines.

X-Arcade runs them at 800x600 via VGA on a daughterboard.

Now I'm left with two issues, the first more important that the second:

1) The monitor is crisp (for an 80s style CRT) near the center, but as you go towards the edges the 'vertical scan lines' become further and further apart, and it starts to look blurry.

By 'blurry" I mean it's hard to read the "File" menu if you put a Windows dialog up there. It's OK in games, but still looks blurrier than I think it should.

2) I do not see convergence rings on the back of this monitor. Is it possible to adjust the convergence? I assume it must be, but if no rings...

I'm a little worried that I've received a bad unit and have been crutching it by turning knobs that I don't even know what I'm doing. The HV Adjust solved 90% of my worries but left me a little spooked and want to get it as good as it should look.


Posted: May-16-2015 5:17 PM
Join Date:May-16-2015
Post: 4

BTW, the monitor is horizontal (landscape). When I mention the 'vertical scan lines' above, I mean that there are black gaps that look like thin scanlines between the pixels.

It's like the further you get out from the center the picture 'expands', but none of the dimensional adjustments change that appearance near the edges

Posted: May-18-2015 9:20 AM
Join Date:May-10-2011
Post: 24

what you discribe is called blooming. It willoccour when the high voltage is groosly out of adjustment. Stop using the monitor immediatly untill you can get a service person to reset your high voltage adjustment correctly. as far as your originol problem ther are adjustments to bring up the other 2 guns if they are within range. as far as your static convergence rings yes it is common on some later tubes not to use the statick rings. The manufacture of the tube is so pricise that static convergence is achieved simply with yoke positioning.

Posted: May-18-2015 3:12 PM
Join Date:May-16-2015
Post: 4

My understanding of blooming though is that when the picture becomes brighter it will expand - I'm not seeing that at all. The picture does not move at all based on overall brightness, and in fact, never moves or expands at all.

Other than the basic RGB config in the onscreen display, there do not seem to be drive and cutoff pots.

Are you sure we're talking about blooming even if the picture does not expand?


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